Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: FourTravelers on December 03, 2015, 11:12:31 pm
Title: Allison Retarder switch
Post by: FourTravelers on December 03, 2015, 11:12:31 pm
We have the MD3060R with the rocker switch (no joystick) My question is....... without the joystick, is there a modification that allows the use of the retarder on downhill grades without having to keep the service brake pedal activated? I don't like riding the brakes for very long. I have always applied the brakes firmly to slow to a safe speed and rpm, then let up until rpms build back up, letting the brakes cool in between. This is in our F250 powerstroke pulling our 30ft TT.
Last week in the coach while coming down the grade on I26 out of Asheville, I had to keep the pedal depressed to keep the retarder active. It's my understanding that this is normal.
Is there a less expensive mod other than the six step joystick? I'm OK with the 3 step brake pressure switches and rocker if it would stay engaged.
Justin
Title: Re: Allison Retarder switch
Post by: Carol & Scott on December 03, 2015, 11:27:11 pm
I have found on most grades that using the transmission gearing is quite effective to "hold" the coach back and the need for constant braking or retarder use is often eliminated. It's the angle of the dangle type of thing. Balance between speed and engine rpm. JMHO :D
I am probably wrong in making this statement but I believe that the retarder is to be used for short periods of time. If used too often or continuously the temp of the retarder might rise too high and the retarder will shut down and might be damaged. Allison Retarder Temperature (http://www.beamalarm.com/Documents/allison_retarder_temperature.html)
I always watch our retarder temp. on the vmspc so it doesn't get tooooooo hot.
Title: Re: Allison Retarder switch
Post by: Duane Budd on December 04, 2015, 07:11:15 am
I have found on most grades that using the transmission gearing is quite effective to "hold" the coach back and the need for constant braking or retarder use is often eliminated. It's the angle of the dangle type of thing. Balance between speed and engine rpm. JMHO :D
I am probably wrong in making this statement but I believe that the retarder is to be used for short periods of time. If used too often or continuously the temp of the retarder might rise too high and the retarder will shut down and might be damaged. Allison Retarder Temperature (http://www.beamalarm.com/Documents/allison_retarder_temperature.html)
I always watch our retarder temp. on the vmspc so it doesn't get tooooooo hot.
The above procedure is the way I used our 1997 U320; down-shifting the transmission into a lower gear for braking going down a slope with intermittent use of the brakes to slow further if needed in curves of the road, etc. Watch those temperatures!
Title: Re: Allison Retarder switch
Post by: D.J. Osborn on December 04, 2015, 07:17:57 am
Is there a less expensive mod other than the six step joystick? I'm OK with the 3 step brake pressure switches and rocker if it would stay engaged.
The joystick is really the best way to control the retarder. The joystick is easily moved between its several positions and that smoothness of operation works extremely well. If you can get one for around $500 then I would consider that money extremely well spent.
Title: Re: Allison Retarder switch
Post by: Miz Dani on December 04, 2015, 08:14:35 am
Gearing into slower speeds downhill (same as the one going uphill especially if it's a steep hill/mountain) & keeping a vigilant eye on both transmission & engine temps + an occasional firm hit on the service brakes will get you thru most anything, but the joystick is a great add-on (mine came with it originally) so the $500 would be well worth it.
This from a relative newbie (& a chick to boot) who just learned recently how to do it right after a near 'emotional breakdown' on a long 7% grade....can't beat the combination of the 3 together, your confidence will soar & you'll be driving more safely & saving your brakes as well.
Title: Re: Allison Retarder switch
Post by: John44 on December 04, 2015, 08:33:32 am
I thought I read on the forum that with the rocker switch version the first position of the retarder activates when you remove your foot from the accelerator pedal.Can easily be checked next time we drive coach.
Title: Re: Allison Retarder switch
Post by: craneman on December 04, 2015, 08:58:11 am
My coach has both, and as I remember the switch gives three stages of resistance depending on brake pressure, nothing when you back off the throttle. On the joy stick the first position is off, then the next operates when you back off the throttle and further positions just more resistance as you move the stick.
Title: Re: Allison Retarder switch
Post by: John44 on December 04, 2015, 09:54:44 am
Will take coach out to warm up to change trans and gear oil,will test retarder then.All you have to do is turn rocker switch on and coast and see if the light comes on during that coasting.Not sure but maybe different years of rocker switch retarders are wired differently.
Title: Re: Allison Retarder switch
Post by: D.J. Osborn on December 04, 2015, 10:07:51 am
My coach has both, and as I remember the switch gives three stages of resistance depending on brake pressure, nothing when you back off the throttle. On the joy stick the first position is off, then the next operates when you back off the throttle and further positions just more resistance as you move the stick.
Ours operates just as you have described it.
Title: Re: Allison Retarder switch
Post by: Chuck & Jeannie on December 04, 2015, 11:30:51 am
Not having a retarder, I am listening to this discussion thread with great interest. Pertinent to the most recent entries, I have often wondered if constantly using the retarder, especially around town, has a adverse impact on fuel mileage. One of the more useful "hypermiling" techniques (which I try to practice) is to accelerate to the desired speed, then "coast" as much as possible. It sounds to me like the "joy stick" retarder, if left "ON" (step 1 or 2) all the time, would not allow this driving mode. You would either have to be accelerating, or else maintaining your desired speed with some amount of throttle, between stops. The "switch" activated retarder, on the other hand, sounds like it would allow free coasting between stops, while still being instantly available when the brakes are applied. In this respect, it would seem to be a more "economical" option.
Any comments from actual users?
Title: Re: Allison Retarder switch
Post by: Tim Fiedler on December 04, 2015, 11:36:55 am
Selecting "on" immediately applies retarder when you lift off throttle. Handy for garbage trucks in the city. RV? Not so much, and economy will suffer
Title: Re: Allison Retarder switch
Post by: Caflashbob on December 04, 2015, 11:50:42 am
In medium crowded freeway traffic in Southern California I do use the retarder. Normally set at position #2 on the controller.
Guru buddy moved mine to the second row up from the bottom on the left hand console which fits my seating position very well.
Mine seems different as mine had been installed to have the lever move forward to increase its operation not back.
In seeing posts about the retarder operation that mentions downshifting to increase its effectiveness I always thought the retarders operation was not engine rpm connected.
Of course downshifting the motor to increase its compression braking is helpful and may be part of the engines abd trans programming as a help but my dim memory is the retarder is a seperate piece on the rear of the trans?
Title: Re: Allison Retarder switch
Post by: wolfe10 on December 04, 2015, 12:19:17 pm
Not having a retarder, I am listening to this discussion thread with great interest. Pertinent to the most recent entries, I have often wondered if constantly using the retarder, especially around town, has a adverse impact on fuel mileage. One of the more useful "hypermiling" techniques (which I try to practice) is to accelerate to the desired speed, then "coast" as much as possible. It sounds to me like the "joy stick" retarder, if left "ON" (step 1 or 2) all the time, would not allow this driving mode. You would either have to be accelerating, or else maintaining your desired speed with some amount of throttle, between stops. The "switch" activated retarder, on the other hand, sounds like it would allow free coasting between stops, while still being instantly available when the brakes are applied. In this respect, it would seem to be a more "economical" option.
Any comments from actual users?
There is no need to leave the joystick in any "on" position. I normally leave the rocker switch in the "on" position and the joystick far forward (or "off"). This allows free coasting when the accelerator is released, and yet the joystick is readily available for smooth deceleration without use of the service brakes when desired. The service brakes are required to come to a complete stop, but the joystick-controlled retarder will provide nearly all of the deceleration.
To me, at least, it's a highly-desirable setup. I wouldn't want to be without it!
Title: Re: Allison Retarder switch
Post by: squeezer on December 04, 2015, 01:09:02 pm
Am I the only one who actively selects the retarder joystick position pretty much all the time?
Normal operation in our coach.
Retarder switch is on by default. (I really don't see a reason to turn it off)
It stays on with the joystick in 0 for light traffic freeway driving. The coach will coast just fine in this mode and it engages just like the service brakes.
Joystick in position 1: Used in light traffic on the freeway and low speed stop and go. The throttle acts as an on/off switch or coast controler.
Joystick position 2/3: Used as above but in heavier traffic. Again this is stop and go type stuff when you want instant control.
Joystick 4/5: Active hill descents or high effort braking.
My left hand is on the wheel or the stick and a lot of times back and forth in quick succession. I have No reservation about selecting full engagement at any time for any length of time. Put it another way, would you rather have your transmission fail from high temps on a long downhill or your service brakes. I really think that folks are a bit to worried about the 4000 series Allison's that most of us have. That is a severe service transmission with literally an unlimited GVW rating from Allison. Are there any documented failures from over use in our application? I believe the only way to hurt one would be with dirty fluid...
And to frame this up I had the unfortunate experience of bailing out of a Mack at 50MPH a few decades ago on a long downhill that turned into an uncontrolled decent... Never want to have that opportunity again!
Title: Re: Allison Retarder switch
Post by: Doug W. on December 04, 2015, 01:40:36 pm
Am I the only one who actively selects the retarder joystick position pretty much all the time?
I don't want this to be taken the wrong way, but I'm another active joystick user.
Title: Re: Allison Retarder switch
Post by: Ted & Karen on December 04, 2015, 02:21:53 pm
I use my retarder like you do Squeezer all the time. I have Amsoil Torque Drive synthetic fluid in my tranny and I do watch the temps on my VMS-PC. I love it and it works great combined with proper gearing coming down mountains and watching speeds and temps. It is one big reason for my getting our Foretravel........... ^.^d
Title: Re: Allison Retarder switch
Post by: wolfe10 on December 04, 2015, 03:01:00 pm
And, some of us use the Allison the same way. Motorhomes are the ONLY automatic transmission vehicles we have ever owned. So, I am glad the Allison 3000 and 4000 allow you to pretty much choose what YOU want.
WHY??? Well, pure physics dictates that a transmission is REACTIVE, reacting to what happened behind you. And the heavier the vehicle the more the momentum, the further behind you it is.
But, a driver can choose to be PROACTIVE. Again this is a choice-- I have no problem with those who just use "D". But a driver can see what is happening in front of him. Downshift earlier if a steep grade is coming up, Downshift and hold it in the lower gear for descents. And by using the mode button AND the up/down arrows, pretty much choose the gear you want to be in.
Title: Re: Allison Retarder switch
Post by: squeezer on December 04, 2015, 03:47:07 pm
And, some of us use the Allison the same way. Motorhomes are the ONLY automatic transmission vehicles we have ever owned. So, I am glad the Allison 3000 and 4000 allow you to pretty much choose what YOU want.
WHY??? Well, pure physics dictates that a transmission is REACTIVE, reacting to what happened behind you. And the heavier the vehicle the more the momentum, the further behind you it is.
But, a driver can choose to be PROACTIVE. Again this is a choice-- I have no problem with those who just use "D". But a driver can see what is happening in front of him. Downshift earlier if a steep grade is coming up, Downshift and hold it in the lower gear for descents. And by using the mode button AND the up/down arrows, pretty much choose the gear you want to be in.
So to clarify, you use gear selection and engine braking alone or gear selection plus retarder?
The old trucker adage that you go down the mountain in the same gear you go up the mountain doesn't work for me as we can go up at a much faster rate than I am comfortable going down...
Title: Re: Allison Retarder switch
Post by: Roger & Susan in Home2 on December 04, 2015, 04:03:10 pm
For descents, my preference is to use gears, retarder and brakes in that order of preference and almost always a mix of all. A lower gear gets you engine braking and higher RPMs which means better cooling. Add in a notch or two or retarder for some additional braking force. Too much retarder because you are at a higher gear just means higher retarder temps. The same downhill speed can be maintained at a lower gear and a bit less retarder and you will manage retarder temps better. It is a balance that comes with some experience. No reason at all to be in a hurry coming down the mountain. Your safety and comfort level should always dictate speeds. If you need to use the air brakes apply them firmly until you have slowed to the speed you want and then release them. Don't ride the brakes. If I am coming up to a curve going downhill those big orange speed signs are my max speeds for my coach. Slow down before you get to the curve. I think you will have better control through the curve if you are not braking.
I use the retarder switch on in traffic for more aggressive braking if I need it.
Do what works for you. Find out what that is. Your safety and comfort level should always be your guide.
Title: Re: Allison Retarder switch
Post by: wolfe10 on December 04, 2015, 04:23:59 pm
So to clarify, you use gear selection and engine braking alone or gear selection plus retarder?
The old trucker adage that you go down the mountain in the same gear you go up the mountain doesn't work for me as we can go up at a much faster rate than I am comfortable going down...
Depends on what auxiliary braking the coach has. But, yes, gears in combination with exhaust brake, engine compression brake or retarder.
Title: Re: Allison Retarder switch
Post by: speedbird1 on December 04, 2015, 05:06:29 pm
As Roger says and in that order. Get slowed up before the curve and don't brake halfway around it. Brian.
Title: Re: Allison Retarder switch
Post by: Caflashbob on December 04, 2015, 05:22:12 pm
If you always use the retarder the brakes tend to glaze. In a low traction emergency which is obviously rare the retarder is supposed to be turned off.
I like playing with the disk brakes. Keeps me aware of the coaches limitations. Warmed up and deglazed they are almost race quality.
If they do not stop well then that to me would be a signal to have them inspected.
Lots here have reported corroded brake pins and irregularly worn pads because of it.
The retarder can cover up brake issues in my experience.
After having driven countless SOB's with average brakes and a somewhat limited capacity engine or exhaust brake the meritor disks are much safer.
Unfortunately designed for much heavier vehicles so they tend to glaze up and not be at operating temp in normal use.
Most here used to leave their retarder on always. I am glad to see some owners exercising the brakes.
My brakes used to not release completely from over greasing and/or dirty pins. Redoing them several times($$$) and adding the helper springs has so far reduced this to zero.
Plus regular hard use during any drive.
Title: Re: Allison Retarder switch
Post by: craneman on December 04, 2015, 08:00:26 pm
If you always use the retarder the brakes tend to glaze. In a low traction emergency which is obviously rare the retarder is supposed to be turned off.
I like playing with the disk brakes. Keeps me aware of the coaches limitations. Warmed up and deglazed they are almost race quality.
If they do not stop well then that to me would be a signal to have them inspected.
Lots here have reported corroded brake pins and irregularly worn pads because of it.
The retarder can cover up brake issues in my experience.
After having driven countless SOB's with average brakes and a somewhat limited capacity engine or exhaust brake the meritor disks are much safer.
Unfortunately designed for much heavier vehicles so they tend to glaze up and not be at operating temp in normal use.
Most here used to leave their retarder on always. I am glad to see some owners exercising the brakes.
My brakes used to not release completely from over greasing and/or dirty pins. Redoing them several times($$$) and adding the helper springs has so far reduced this to zero.
Plus regular hard use during any drive.
I take it not all Foretravels have 4 wheel disc brakes? The 1999 U320 has them
Title: Re: Allison Retarder switch
Post by: FourTravelers on December 04, 2015, 08:02:32 pm
My coach has both, and as I remember the switch gives three stages of resistance depending on brake pressure, nothing when you back off the throttle. On the joy stick the first position is off, then the next operates when you back off the throttle and further positions just more resistance as you move the stick.
Just to clarify...... If I add the joystick and also keep the rocker switch, I can use the retarder as I do now with only the brake pedal (pressure) actuation OR I can use the joystick in one five positions and the retarder will activate when the accelerator pedal is released?
Is there a switch that must be added to the accelerator pedal to send the signal to the Allison?
Title: Re: Allison Retarder switch
Post by: Caflashbob on December 04, 2015, 08:20:39 pm
Just to clarify...... If I add the joystick and also keep the rocker switch, I can use the retarder as I do now with only the brake pedal (pressure) actuation OR I can use the joystick in one five positions and the retarder will activate when the accelerator pedal is released?
Is there a switch that must be added to the accelerator pedal to send the signal to the Allison?
That is a question I can.t answer as mine came with both. I would guess that the joy stick installation would come with all hardware necessary.
Title: Re: Allison Retarder switch
Post by: red tractor on December 04, 2015, 09:36:46 pm
You do not need to add another switch to make the allison work
Title: Re: Allison Retarder switch
Post by: Pamela & Mike on December 04, 2015, 09:40:32 pm
Is there a switch that must be added to the accelerator pedal to send the signal to the Allison?
The switch is not added to the accelerator pedal but is a patch cord that hooks to your transmission ECM and joy stick.
You should need the rheostat/joy stick (295-21372) and depending on if your coach has the retarder control kit you will need one of those (it will be hid behind the kick panel at your left foot) along with the Allison ECM. Be sure to check which control kit you need as there are several versions.
Pamela & Mike
Title: Re: Allison Retarder switch
Post by: D.J. Osborn on December 05, 2015, 08:05:12 am
Just to clarify...... If I add the joystick and also keep the rocker switch, I can use the retarder as I do now with only the brake pedal (pressure) actuation OR I can use the joystick in one five positions and the retarder will activate when the accelerator pedal is released?
That is correct. You can add the joystick and if you have the rocker switch "on" with the joystick in the farthest-forward position the retarder will be activated with brake pedal pressure but will not be automatically activated when you release the accelerator. If you move the joystick back one position then the retarder will begin to activate automatically when the accelerator is released.
Title: Re: Allison Retarder switch
Post by: FourTravelers on December 05, 2015, 08:25:58 am
thanks D.J.Osborn, sounds like the best option, I'll start looking for a good price on the joystick and Y connector.
We are planning on a 7500 mile "out west" trip next summer, would like to have it before then.
Thanks to all for the information
Title: Re: Allison Retarder switch
Post by: D.J. Osborn on December 05, 2015, 10:57:21 am
sounds like the best option, I'll start looking for a good price on the joystick and Y connector.
We are planning on a 7500 mile "out west" trip next summer, would like to have it before then.
I highly recommend having the retarder (with joystick control) for any serious mountain driving. We haven't yet used our Foretravel for any significant mountain driving in the West, but it certainly has been an important safety device on roads such as I-64 in West Virginia. It is very useful on long 6% downgrades for maintaining the proper speed with almost no use of the service brakes. I really like descending a steep mountain knowing that I'm keeping the service brakes at a nice temperature in case any sudden stop is required. I hope to never again drive a large motorhome without a transmission retarder!
Title: Re: Allison Retarder switch
Post by: Mike Leary (RIP) on December 05, 2015, 11:20:31 am
Quote from: D.J. Osborn link=msg=218450 date=14493310 We haven't yet used our Foretravel for any significant mountain driving in the West[/quote
You will be happy ( & safe) to have all the braking possible out here. There is a drop in NE Wyoming that I later learned was called, "Oh my gawd hill". http://www.mountaindirectory.com/ dangerousroads (http://www.dangerousroads.org/)
Title: Re: Allison Retarder switch
Post by: Capt.SRP on December 05, 2015, 10:19:01 pm
I just purchased the Y connector from Foretravel, Part # P28173 Hand Retard wire harness $23.08 plus shipping.
I ordered the Joystick and Module from Ted at TKT Sales Part # 29521372 Retarder control lever $309.23 Part # 29506474 Resistance Module $123.62 Plus shipping
My understanding is these are the main parts required to add the Joystick to the coach. There is also a relay that can be added so the Brake lights come on when the Joystick is used.
I am a newbie so I am sure other forum members have more information on this issue. I thought the current prices might be helpful.
Title: Re: Allison Retarder switch
Post by: Irwin on December 05, 2015, 11:15:17 pm
Here is a little bit of information on Allison retarder operation and hookup. FWIW Irwin
Title: Re: Allison Retarder switch
Post by: FourTravelers on December 06, 2015, 08:00:58 am
Thanks Capt.SRP and Irwin for that info................ appreciated!
Title: Re: Allison Retarder switch
Post by: speedbird1 on December 06, 2015, 10:21:27 am
Thanks Irwin, That should be required reading by all FT owners with the retarder system, and would have eliminated some of the other theorys out there. And, some of the surprises that have happened over the years. I wish it had been in the manual that came with the coach, or had been mentioned by FT when I bought mine. But, only valid on coaches that have not been messed with, and changes made to the operation of the system. Brian.
Title: Re: Allison Retarder switch
Post by: Caflashbob on December 06, 2015, 11:57:09 am
Interesting that Allison offers a retarder pedal. Infinitely variable not 6 position.
Title: Re: Allison Retarder switch
Post by: Pamela & Mike on December 06, 2015, 07:36:45 pm
Interesting that Allison offers a retarder pedal. Infinitely variable not 6 position.
We drove a Newell with one of the foot control retarder controls. Mike said that it has the effect of being a drummer in a stage band. Just like anything new, you would have to get familiar with it's operation. We couldn't tell any difference in how the foot control works compared to the hand control we have now.
Pamela & Mike
Title: Re: Allison Retarder switch
Post by: Caflashbob on December 06, 2015, 07:40:10 pm
We drove a Newell with one of the foot control retarder controls. Mike said that it has the effect of being a drummer in a stage band. Just like anything new, you would have to get familiar with it's operation. We couldn't tell any difference in how the foot control works compared to the hand control we have now.
Pamela & Mike
Where was the pedal located? Did it have a lever also?
Title: Re: Allison Retarder switch
Post by: Pamela & Mike on December 06, 2015, 08:16:02 pm
1.Where was the pedal located? 2.Did it have a lever also?
1. Located in the same area as where your dimmer switch use to be located prior to it being put on the turn signal switch. (or said another way just left of the steering column) 2. No hand lever just the foot control.
Pamela & Mike
Title: Re: Allison Retarder switch
Post by: Caflashbob on December 06, 2015, 08:20:13 pm
1. Located in the same area as where your dimmer switch use to be located prior to it being put on the turn signal switch. (or said another way just left of the steering column) 2. No hand lever just the foot control.
Pamela & Mike
Ah left foot braking...thanks .
Wonder if both the pedal and lever could be installed? Might as well be a drummer
Title: Re: Allison Retarder switch
Post by: AC7880 on September 07, 2016, 01:12:08 pm
Old thread, new related question.
I would want the retarder to NOT light up the brake lights in the rear. Is that easily accomplished? Year models (future purchase) would be 2001 to 2004 U320.
Reason: coming down a long grade with controlled descent I don't want the brake lights on the entire time. If I need to brake harder with service brakes for some roadside problem, that is when I want the brake lights to first light up to warn those behind me (especially the occasional tail gaiters).
Title: Re: Allison Retarder switch
Post by: D.J. Osborn on September 07, 2016, 01:21:51 pm
I would want the retarder to NOT light up the brake lights in the rear. Is that easily accomplished? Year models (future purchase) would be 2001 to 2004 U320.
I can't speak for other years, but the retarder on our 1995 does not activate the brake lights.
Title: Re: Allison Retarder switch
Post by: Caflashbob on September 07, 2016, 01:35:09 pm
Our 97 has a popular owner/dealer mod where the retarder works on cruise control.
I think the brake lights come on also.
Title: Re: Allison Retarder switch
Post by: craneman on September 07, 2016, 01:44:21 pm
The factory install on my '99 brake lights come on with retarder. Don't know if I would want it any other way. Going down a grade using the retarder I will be slower than prevailing traffic and I want them to know that.
Title: Re: Allison Retarder switch
Post by: Barry & Cindy on September 07, 2016, 01:51:53 pm
We have a dash switch that we installed to choose if we want brake lights on with retard. Useful to for Dan's reason, but more useful to not drop out of cruise when driving on highway with joy stick in retard positions. When retard turns on brake light: on slight down hills, throttle comes up, retard comes on, brake light comes on dropping cruise.
With our switch normally in no brake light with retard: on slight down hills, throttle comes up, retard comes on, brake light does not drop cruise, and on bottom of hill throttle kicks back on, turning off retard, and off we go driving down the highway in cruise control.
Of course, if we had the joy stick in zero retard position, cruise would not kick off on down hills.
Generally, King Cruise Control is connected to brake light switch wire, so it knows to turn off when 12-volts are lighting brake lights. So if Bob & Susan have retard brake lights without dropping cruise, their coach could be wired differently.
Title: Re: Allison Retarder switch
Post by: Barry & Cindy on September 07, 2016, 02:20:40 pm
The story on why some coaches have brake lights with retard and others don't goes back to the time Foretravel installed Allison transmission retarders that were brake pedal activated, but did not have the operator activated joy stick. And since brake pedal already activates brake lights, there was no need for retard to also activate brake lights.
When joy stick was standard factory installed equipment, brake lights come on with either or both joy stick and brake pedal.
In between no joy stick and factory installed joy stick years, Foretravel service or others were buying Allison joy sticks and installing them on side panel in an open switch position. Some installed with full retard pulled back (like ours) and others installed the joy stick with full retard pushed forward. Just how the joy stick was mounted.
After market joy stick used a "y" splitter cable that connected the new joy stick to the Allison wiring plug the brake pedal was using. This added joy stick retard, but without retard brake lights.
The brake pedal uses a pair of air pressure activated switches mounted on forward wall of street side forward compartment to turn on brake lights. Some joy stick installations added a relay next to the air pressure switches that was wired parallel with air switches, so that brake lights turned on with front air brakes, rear air brakes and/or Allison retard.
All installations have a factory relay on the front 12-volt big panel board that is closed when Allison retard is active. This relay does not interact with brake lights. After market joy sticks had a new wire from this front panel factory retard relay to the optional new relay next to the above air brake switches. So when front panel retard relay is closed, the new brake light relay closes, turning on brake lights.
If one puts a dash switch on this new optional added wire, driver can control if brake lights come on with retard or not.
Title: Re: Allison Retarder switch
Post by: Mike Leary (RIP) on September 07, 2016, 02:32:39 pm
Interesting thread. Got me wondering if our Pac-Brake ( with "on/off" switch )activates the brake lights, as well. Not a fan of having that feature, as others have posted.