Brake Lights

[FLYAway1]

On our 2017 Phaeton 36GH neither of our brake lights illuminate. The trailer brake lights function properly. Disconnected the 7 pin trailer plug and coach brake lights still not working. Also, the LED brake light strip doesn’t illuminate. Bulbs check out good. Emergency flashers, turn signals and running light all operate normally. Does anyone have a light wiring schematic. Any suggestions?
Thanks!
Happy Trails,
Ron, Marsha and Piper

[Lt Dan]

In the second to the rear compartment on the passenger side are a couple of fuse/relay blocks. They are high up on the wall of the basement and have black covers over them. The relays and fuses for the taillights and brake lights are in those blocks. There are separate relays and fuses for the trailer connection and the coach rear lights.

[FLYAway1]

As always, THANK YOU Lt. Dan! It is dark and cold outside now but I will take a look in the morning. Hope to get on the road Thursday from Oregon back to Florida. Looking like it might be fun!
Happy Trails!
Ron, Marsha and Piper

[FLYAway1]

Talked to Tiffin Tech and they referred me to Freightliner. Freightliner stated that there are no fuses in the brake ight system. The lights run through a “Multiplex” control in the left front compartment and then through a “Chassis module” located somewhere above the rear axel assembly. As everything but the brake lights work and the bulbs are good, he felt that the issue is with the Chassis module.
Has anyone replaced this module and if so, where exactly was it located. As a note, apparently the emergency flashers and the brake lights use the same filament. If the rear flashers operate, the brake bulbs and wiring is good. The Chassis module is not operating correctly. Second module failure in a month. The Kwikee step module failed earlier.
Happy Trails!
Ron, Marsha and Piper.

[R.M.A]

Do the brake/hazard lights work in the 7 pin for the trailer hitch?

[FLYAway1]

Yes, all 7 pin functions work correctly with the trailer. The 7 pin connector apparently is separate from the light modules.
Happy Trails!
Ron, Marsha and Piper

[R.M.A]

Originally Posted by FLYAway1

Yes, all 7 pin functions work correctly with the trailer. The 7 pin connector apparently is separate from the light modules.
Happy Trails!
Ron, Marsha and Piper

Well, a on the road fix would be to splice into the trailer plug and hook them to your coach lights. 🤷*♂️

[garykk]

Did you look where Lt. Dan said to look?..I have owned a couple of Tiffins now, both Freightliner chassis and Powerglide and BOTH had fuses for the taillights/brakes right where Lt.Dan said.

[FLYAway1]

Yes, I did look in those bays and I thank Lt. Dan for his advice. After looking in those bays and finding no fuses labeled for the chassis brake lights, I called Tiffin tech. They referred me to FL. On our 2017 Phaeton 36GH, those compartments contain fuses for the TOW (7 pin) connections, not the chassis lights. According to FL, chassis lights go through two control modules. It just happens that on this trip, we are towing a 24 foot flatbed trailer. We are moving by using the trailer lights as brake lights and only traveling during the day. We are legal doing this, just like a semi truck. The day only travel is our decision, not a legal decision.
Happy Trails!
Ron, Marsha and Piper

[FLYAway1]

Does anyone have a good manual on how the brake lights work on a 2017 Tiffin 36GH? I am having an issue with my brake light operation and can find no literature on how the system integrates with the exhaust brake and trailer brake controller. Towing a trailer, when the engine brake is operating, the trailer brake lights function alone. The coach brake lights do not illuminate. When the service brakes are applied, the trailer brake lights illuminate and sometimes the coach brake lights illuminate but not always. Stopped, press on the service brakes and only the trailer brake lights illuminate, not the coach brake lights. The brake controller is a high end controller that has a patch plug to connect to the coach factory wiring harness. All trailer light and brake functions operate normally. Both Tiffin and FL tech point fingers back at each other but neither has a clue as to the correct operation of the system and how the different components integrate with each other. FL says to replace the brake module and if that does not fix it, replace the multiplex module. Throwing parts at a problem praying that it will fix the problem is not normally my way of troubleshooting an issue. There are some really sharp people on this forum, hopefully one of you has a good understanding of the system and can explain it so even I can understand. Maybe the best recourse is to unplug the brake controller and 7 pin plug and see what happens. All worked properly prior to this. Everything functioned properly with the TOAD connected via the 7 pin. We are towing a 7,000# trailer and equipment, I would not operate this load without the trailer brakes operational. Unsafe and not legal.
Thanks!
Happy Trails!
Ron, Marsha and Piper
(Somewhere in the wilds of AZ)

[Shawn Cole]

Originally Posted by FLYAway1

Does anyone have a good manual on how the brake lights work on a 2017 Tiffin 36GH? I am having an issue with my brake light operation and can find no literature on how the system integrates with the exhaust brake and trailer brake controller. Towing a trailer, when the engine brake is operating, the trailer brake lights function alone. The coach brake lights do not illuminate. When the service brakes are applied, the trailer brake lights illuminate and sometimes the coach brake lights illuminate but not always. Stopped, press on the service brakes and only the trailer brake lights illuminate, not the coach brake lights. The brake controller is a high end controller that has a patch plug to connect to the coach factory wiring harness. All trailer light and brake functions operate normally. Both Tiffin and FL tech point fingers back at each other but neither has a clue as to the correct operation of the system and how the different components integrate with each other. FL says to replace the brake module and if that does not fix it, replace the multiplex module. Throwing parts at a problem praying that it will fix the problem is not normally my way of troubleshooting an issue. There are some really sharp people on this forum, hopefully one of you has a good understanding of the system and can explain it so even I can understand. Maybe the best recourse is to unplug the brake controller and 7 pin plug and see what happens. All worked properly prior to this. Everything functioned properly with the TOAD connected via the 7 pin. We are towing a 7,000# trailer and equipment, I would not operate this load without the trailer brakes operational. Unsafe and not legal.
Thanks!
Happy Trails!
Ron, Marsha and Piper
(Somewhere in the wilds of AZ)

The brakes lights should work together in unison. If they are not working in this manner, your coach would need to be taken to a repair shop to be diagnosed.

[FLYAway1]

Thank you Shawn. Could you please clarify “in unison”. Does that mean the coach brake lights illuminate when the exhaust brake is active? Should the coach and trailer brake lights illuminate simultaneous with activation of the service brake treadle? The trailer brakes are electric with a controller in the cockpit. Should the coach and trailer brake lights operate with just the exhaust brake operation? I have not found any brake operation guidance in my Tiffin literature. I need to understand how the system is supposed to work so that I can identify if I actually have an issue. As an aside, this brake ight operation issue seemed to start after the parking brake repair fiasco at a Factory Freightliner/Oasis facility. To be fair, we have not previously towed a trailer with electric brakes prior to this repair. The TOAD uses the coach air brake system.
Happy Trails!
Ron, Marsha and Piper

[Lt Dan]

The trailer/toad brake lights and the coach brake lights should work in unison. The brake lights will also work when the exhaust brake is active. You should have separate relays and fuses for the coach brake lights and the trailer connection. Check in the driver's side front compartment high up on the back wall and in the passenger side rear compartments for covered fuse/relay blocks.

[garykk]

How do we know it’s not the high end brake control causing this problem?