So I've looked at my schematic and maybe I'm just dumb but can't seem to figure out what the 2 little switches teeing off the 2 big brakes switches are for. (1st picture)
A guess is something to do with the retarder.
I'm also assuming that the 2 big switches are redundant in case one goes bad correct? And is that the case for the 2 small ones also?
There's also another switch further back up into the dash that I'm not sure is for...and I'm not talking about the 3 bundled together for the auto retarder function. (2nd picture)
Any help would be appreciated, I'm still trying to trouble shoot my cruise control issue and hoping maybe one of these switches is the culprit.
One is probably air pressure gauge and the other is the low pressure warning. Disconnect a wire and find out.
Under dash - does it have a wire labeled T3 or maybe T3M on it? Looking at our old B-2179 schematic, that might be the brake light switch.
Looks like someone got very creative with switches and wiring. I have never seen added switches like that. Maybe the added switches are being used for a brake controller for a trailer or towed vehicle, so that the retarder doesn't activate the brake controller. Just a guess. Probably have to trace where the wires come from and where they go from the added on switches.
I don't think it's for a brake controller, but that is strange that it isn't an OEM configuration. Though maybe an 01 U320 is different than other years.
If you read this Scott, you have an 01...do you remember your brake switches looking like mine?
I have worked on lots of Foretravels and have never seen anything like that. Do the wires have numbers on them? If they do then much easier to figure out. Some people get very creative in what they add to a coach.
It looks like factory wiring? I'll have to take a peek and snap a picture. Like Red Tractor mentioned I too was in there being creative for my brake controller and retarder wiring. I did do a revision to my wiring diagram so someone down the road can make sense of it. I think I may have the additional smaller pressure switches also but will double check. I clearly wanted my retarder not to ever actuate my brake controller.
They do have numbers on them, but from memory don't know what the schematic says, I'll follow up...maybe make my own diagram and show it here.
I have drawn out the best I can the wiring schematic along with wire descriptions. It does look like the 2 small brake switches are OEM, along with the random one at the top left of my drawing.
I've also attached the air routing schematic from the FT manual which shows all 5 of the switches located under my dash, so apparently those are factory installed and wired correctly as far as I can tell...no aftermarket shenanigans.
What I'm trying to track down is a random "brake light" application that is tricking the cruise control to kick off. My bluefire app has a "brake light" icon that lets me know when the brakes are being applied. But randomly that light will stick on thus not allowing my cruise control to work. Furthermore, when that light is stuck on, the actual brake lights are NOT stuck on, so this has something to do with one of the wires associated with the Engine or Tranny ECM...possibly.
Some of you know I've been chasing my tail on this for some time now, but I think I'm getting close. The problem is I really need to trouble shoot when the brake light is stuck on and that usually doesn't happen until I have been driving for awhile, so hard to chase it down at home. Also, I can tell if the cruise is working correctly at home because the high idle works, but doesn't work when the brake light icon in bluefire is "stuck" on, which makes sense since they use the same functionality to operate.
Random electrical issues are the worst nightmare anyone can have in my opinion.
Yes I think you are going the the correct direction with an intermittent switch or wire shorting out. Interesting the blue fire showing a brake application, cancelling your cruise control would be it doing its job correctly. I've used light diodes for many purposes like failed fuses and intermittent circuits because when activated they can illuminate giving real time trouble shooting information. You may only see a flicker but this would isolate which circuit it is . Could gang them all together on a piece of cardboard and mount where you could view them while operating. Just throwing out ideas? Crazy to be chasing a cruise control issue only to find out it was a hidden brake light issue. Cool find
Trying to do a little forum digging into this to see if there's any previous discussion.
Mention of sticking break switch and also possible relay gone bad, note Neal's post above Barry and Cindy's as well:
Sticky Brake Light Switch (https://www.foreforums.com/index.php?topic=10727.msg51014#msg51014)
And I think this is similar, but in this one the pressure switch for the retarder being the one "sticking" Retarder control assembly, brake (https://www.foreforums.com/index.php?topic=26453.msg212334#msg212334)
Maybe you could make your own test light to put on what circuit you want to test so you could have it hooked
up while driving so when the light comes on in your bluefire you could coordinate it. It's a bitch when things
go haywire when you can't trouble shoot it.
Thank you, I've read those....and probably every post that has anything to do with cruise control, braking, and the retarder. I might be thinking about this wrong, but I feel if a brake light switch is physically not working correctly or sticking wouldn't it make the brake lights stick on? My actual brake lights out back are not stuck on when the cruise is not working correctly.
that's 2 of you that suggested to rig up a test light...probably what I'll need to do...and figure out which wires to test...
...and Scott, it's only cool cuz it's not your coach 😁
A poor photo, but I put a "brake light" in my dash 12 years ago. I too suffered through intermittent cruise drop outs and occasional power loss before I finally tracked my problem to a flakey brake switch...no problems since, but at least now I know if/when a signal is sent to my brake lights. That intermittent stuff can cause hair loss.....
Definitely a love/hate relationship
Ive even considered putting LEDs on everything and wish I had during this last Bronco build. Seems kinda redundant but imagine having instant trouble shooting aids on everything. IE headlight out but LED indicates power at bulb plug. Could incorporate on everything. Starter? Headlights? Horn relay? Endless list. Does take a few pennies and the time to incorporate.
That would be quite a project but as much as these older rigs cause us problems it would be worth it.