Community Forums

robertsons · 08-14-2021, 07:50 PM

Our 2018 Allegro Red QRA brake lights have quit working. Blinkers, and tail lights work but no brake. We cannot find the fusebox for the lights. Anyone know where to look. Book says under dash but we are not able to locate a fuse box in the dash panel.
Any help would be appreciated. We are stuck in a campground in northern MI until we can get this fixed.

**Lt Dan** · 08-14-2021, 10:41 PM

Look in the second to last or last compartment on the passenger side. There is a couple of fuse blocks there with black covers. The relays and fuses for the turn signals should be in there.

dabrooks · 08-15-2021, 05:11 AM

I would start by checking the brake light switch at the brake pedal.

jeskibuff · 08-15-2021, 07:12 AM

Quote:

Originally Posted by Lt Dan

Look in the second to last or last compartment on the passenger side. There is a couple of fuse blocks there with black covers. The relays and fuses for the turn signals should be in there.

If one of those you're referring to is the PDM (Power Distribution Module), that one wouldn't have relays for the coach's brake lights. It merely translates signals from the turn signals/brake pedal/running lights to the tow connector but that would be an easier way to test the brake pedal instead of crawling under the dash. I think (not sure) that when the brake pedal is pressed that both the left and right turn signal relays should engage so if someone in the coach repeatedly presses the brake pedal you should hear those relays clicking on and off. To easily locate the module, you should be able to hear the relays clicking if you turn on either turn signal. If those work but pressing the brake pedal does nothing then the problem is further upstream...like the pedal switch. If the relays do make a clicking sound when pressing the brake pedal repeatedly then there's either a fuse blown for the brake lights or they (unlikely) have burned out.

jeskibuff · 08-15-2021, 07:18 AM

Attached is the map found on the inside of the cover of the PDM. The relays that actuate the turn signals on the tow connector are labeled "TOW LH TRN RLY" and "TOW RH TRN RLY". Notice that there is no relay for brake lights since actuating the brake pedal merely causes both turn signals on the towed vehicle to be illuminated.

millerj · 08-15-2021, 06:38 PM

This may not apply to your model Tiffin motor home but on my 2020 Allegro Open Road 32sa the fuse for the brake and turn signals is under the steering wheel on the left side and is a 20 amp fuse. I believe this fuse may control both the brake lights and turn signals but not positive.

neilj · 08-17-2021, 08:26 AM

Quote:

Originally Posted by jeskibuff

I think (not sure) that when the brake pedal is pressed that both the left and right turn signal relays should engage so if someone in the coach repeatedly presses the brake pedal you should hear those relays clicking on and off.

I have the same issue, I called Tiffin and was told there is not a fuse for the brake lights because it runs through the Spyder system (got me on that one). I looked in the same panel on PS 2nd to last bay but drew a blank because it appears like mentioned earlier this panel is only for TOAD lights which all work, brake & turn signal.
I did not listen for any clicking, probably will try that.

I do have a question on pressing on the brake pedal, does the motor need to be running for the brake lights to work or just key in the on position?

I haven't checked under the steering column yet but was going to try that.

jeskibuff · 08-17-2021, 09:46 AM

Quote:

Originally Posted by neilj

TOAD lights which all work, brake & turn signal.
I did not listen for any clicking, probably will try that.

If the toad brake lights are activated when you press the motorhome's brake pedal, you know that the brake pedal switch is working. No need to listen for clicking, as the only purpose that serves is to help locate the PDM in your rig if you didn't know where it was.

That would focus the problem somewhere between the brake light lamps and the wire from the brake pedal switch. That really sounds like a fuse somewhere. It doesn't make any sense to me that it'd be in the Spyder system but I suppose Tiffin should know better. Still, any device which draws current should (I think) be fused to protect both the device and the wiring to it.

neilj · 08-17-2021, 10:13 AM

Quote:

Originally Posted by jeskibuff

That would focus the problem somewhere between the brake light lamps and the wire from the brake pedal switch. That really sounds like a fuse somewhere. It doesn't make any sense to me that it'd be in the Spyder system but I suppose Tiffin should know better. Still, any device which draws current should (I think) be fused to protect both the device and the wiring to it.

Sounds like I really need to look under the steering column. I would have to think there is some sort of fuse somewhere like you say.

dabrooks · 08-17-2021, 10:38 AM

I am not sure but I believe that the brake light signal passes through the same wires as the turn signals. Again I would start at the switch at the brake pedal.

jeskibuff · 08-17-2021, 07:17 PM

Quote:

Originally Posted by neilj

I do have a question on pressing on the brake pedal, does the motor need to be running for the brake lights to work or just key in the on position?

I just confirmed that my brake lights will go on by depressing the pedal even if there's no key in the ignition. I'm betting yours works the same way.

chuckftboy · 08-17-2021, 08:34 PM

I think you are experiencing a power distribution failure (PDM). Your 2018 is most likely on a Freightliner XC Chassis and there was a recall on the PDM. I just had mine replaced last week, lost all tail lights on the right side. The PDM will be close to the rear and probably in the last bay. You can search PDM failure on this site for a lot of info or just google it for a ton of information.

These have printed circuit boards and relays and there is a series of serial numbers that had weak solder joints that fail

jeskibuff · 08-18-2021, 07:38 AM

Quote:

Originally Posted by chuckftboy

I think you are experiencing a power distribution failure (PDM). Your 2018 is most likely on a Freightliner XC Chassis and there was a recall on the PDM. I just had mine replaced last week, lost all tail lights on the right side.

Perhaps your PDM is different from mine but I'm sure I could completely unplug my PDM and all coach turn signals & brake lights would function normally. Mine only handles tow connector functions and other things like DEF heater, transmission control, etc. Could be they use a different PDM on the XC chassis than what I have?

robertsons · 08-18-2021, 07:52 AM

Thank you everyone for your help to the Robertsons. We don't really know how we got it fixed. After doing lots of searching under the dash panel and steering wheel and coming up empty. We tried prayer and pushing every circuit breaker in the first bin under the drivers side. Whatever we wiggled, or prayer answered. We have lights again and were able to continue on.
Will check on the recall from freightliner that was mentioned and see if we would be included.
Again, thanks to everyone.