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Topic: Dead Dash Air (Read 760 times) previous topic - next topic

Dead Dash Air

Hi All,

While traveling from Phoenix to Flagstaff a few weeks back in the 110 degree heat, our Dash AC abruptly stopped working.  Coolant temp was high at 210 when climbing, but that has not caused issues previously.    The dash blower or fan will still work when the control is set to vent or heat, but fan will not work when set to AC.  Curious if something tripped or it's a bad relay?    Any suggestions to remedy the loss of Dash AC would be greatly appreciated!!   
Muri: 2003 U295 3620

Re: Dead Dash Air

Reply #1 –
May be low on Freon,if you have a preferred auto mechanic he could probably troubleshoot it.Can you look at your ac
compressor when the engine is running to see if it is coming on?
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Dead Dash Air

Reply #2 –
Quote from: TLandon –
Hi All,

While traveling from Phoenix to Flagstaff a few weeks back in the 110 degree heat, our Dash AC abruptly stopped working.  Coolant temp was high at 210 when climbing, but that has not caused issues previously.   

Hmm, We know that I-17 hill very well, I tried to avoid it in high temps, and always shut down the dash air. Even so, I finally switched to going up "The Beeline" thru Payson during this weather. I wonder if the heat trashed the compressor?
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
Previous: 1983 Airstream 310 turbo diesel, 1979 Airstream 280 turbo diesel
                                      Build # 4297
                                      PNW natives
                      Home base:  'Cactus Hug' (Ajo, Arizona)
                        DW Judy & Chet the wonder dog
                        Full-Timers 'Sailing the asphalt sea'

Re: Dead Dash Air

Reply #3 –
No, low freon will not cause the dash HVAC fan to not work.

So, the fan doesn't work on any speed?  Only on A/C or in any other position?
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Dead Dash Air

Reply #4 –
I would work the selector switch back and forth a bit to see if the dash fan comes on... if it does, perhaps some DeOxyit contact cleaner would help.
Don
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Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Dead Dash Air

Reply #5 –
On that I-17 pull, and the pull to Payson, there are signs that warn about running a.c.
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
Previous: 1983 Airstream 310 turbo diesel, 1979 Airstream 280 turbo diesel
                                      Build # 4297
                                      PNW natives
                      Home base:  'Cactus Hug' (Ajo, Arizona)
                        DW Judy & Chet the wonder dog
                        Full-Timers 'Sailing the asphalt sea'

Re: Dead Dash Air

Reply #6 –
 can you post a picture of your dash air control, is it the dodge one or do you know?
1988  40' Grand Villa Cat 3208t

Re: Dead Dash Air

Reply #7 –
I will snap a photo tomorrow.  The fan runs when the dial is set to vent or heat.  The fan will not run when the dial is set to AC.  So I was thinking it may be an electrical issue???

Yes, the climb to Flagstaff is a necessary evil for us!  We also climbed several awesome roads this summer that make the I17 look easy, such as CA 190 to Camp Nelson, CA, CA 180 to Sequoia NP, and Mt Whitney portal Road with 9% grades.  Loads of fun!!

Thanks for the help!!
Muri: 2003 U295 3620

Re: Dead Dash Air

Reply #8 –
Quote from: TLandon –
So I was thinking it may be an electrical issue???
I would have a tendency to agree, but I'm not 100% sure.  Was the system cooling well right up to when it stopped? 
If so that would also indicate an electrical issue in my mind.  I had a similar problem but it only occurred on high speed.
It turned out to be an intermittently bad auto relay that is only used on high speed.  The lower fan speeds worked fine.

One suggestion is to try the defrost.  Most systems run the A/C automatically when defrost is selected.  Others require the user to turn the A/C button on.  Might be insightful to see what your does.
You should be able to see and hear the compressor clutch cycle on the engine or notice cold air coming out of the defrost vents.

Also, with the A/C turned on, have you checked to see if the compressor is running (despite the fan not running)?

Another suggestion is to look through the schematics in your FT notebooks - there's loads of information that just might point you in the right direction.
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho

Re: Dead Dash Air

Reply #9 –
Here is a photo of AC controls:

As I started coach up today, I was able to turn AC on and the fan ran for about 30 seconds and then quit.  As I turn the dial from AC to vent to heat and to defrost, the fan now only runs on vent and heat.  Fan stops as I turn to defrost, as FT manual reads that AC condenser is activated on the defrost setting.    As I rotate dial through settings, the light in the Driver Information Center flashes or dims momentarily and I hear a clicking noise within the dash - like there is a power drain to dash and then a breaker or something trips to release current draw on the dash electronics. 

Any ideas??  Thanks again!
Muri: 2003 U295 3620

Re: Dead Dash Air

Reply #10 –
Have a AC Guy look at it,
1988  40' Grand Villa Cat 3208t

Re: Dead Dash Air

Reply #11 –
Could also be a loose connection.  Particularly check the grounds.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Dead Dash Air

Reply #12 –
T,

Your unit has 2 breakers that feed the dash air  #'s 33 & 34.(IIRC)  They are hid behind the kick panel just as you come in the front door on your right  hand side.  They are self resetting and it sounds like one may have gotten week and is tripping out.  If you pull out your B-2179 print look to see which feeds the high blower and which feeds the rest of the system. I can't remember setting here.  New breakers can be found at most good parts stores.    The big problem is getting the buss bar off the other breakers (seems like there are 3 on this buss) so you can change them out.  If it was me I would changes both of them out while you have the buss bar off.  They should be 20 amp breakers.  ~ $3.00 or $4.00 each.

You may also have a dash blower fan starting  to bind up causing the breakers to trip. So you may want to check the amp draw to see if the blower motor is drawing too much or is it a week breaker.

Pamela & Mike

Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Dead Dash Air

Reply #13 –
FY,I  many  FT's  came from the factory with a "vacuum generator" that uses compressed air from the air/ride system to create vacuum.  Well, the factory deemed it necessary to plumb the generator into the parking brake system.  Vacuum will only be created when the parking brake is off, so all that time you are sitting in a parking lot idling you can't have dash air unless your parking brake is off.  The solution is to add a 12v vacuum pump available on Ebay for about $50.00 to power your dash air vacuum needs.
1988  40' Grand Villa Cat 3208t

Re: Dead Dash Air

Reply #14 –
Yours if different than ours but I would check to see if the A/C compressor clutch is engaging and the compressor is turning. If not the clutch could be shorted to ground and drawing enough current to trip the A/C breaker. You could unplug the electrical connector going to the clutch and see if the fan will run without the compressor.

What you describe sounds like a short circuit, dim lights could be a lose connection but you mentioned it sounds like a breaker trips.
Justin & Cathy Byrd
1995 U280 "Old Faithful"
36' Build #4673
C8.3 Cummins
Allison MD3060R 6 speed - retarder
Powertech 10KW  4cyl Kubota

Re: Dead Dash Air

Reply #15 –
I think four travlers is on the right track for sure check out the compressor causing the fan to quit
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins