Brake lights don't work

[CJW8]

It is a 2004 Winnebago Vectra Class A diesel Pusher. The brake lights don't work but the 3rd brake light does. I believe the 3rd brake light is on it's own circuit. The blinkers and emergence flashers work so the 6 bulbs are good. Also the trailer brake lights don't work. The brake switch is a pneumatic pressure switch and I get voltage from the pressure switch when the brakes are applied. I have checked every fuse I can find that has anything to do with the brakes and several relays with no luck. Any help would be appreciated.

[CJW8]

RLS7201 wrote:
If you have yellow turn signal lenses (5 wire system), then the brake lights and turn signals are on different wires and the brake light circuit does not go through the turn signal switch. Other wise you have a 3 wire system.

Richard

It is all red lights with 2 filament bulbs.

[CJW8]

ROBERTSUNRUS wrote:
🙂 Hi, it might be the turn signal switch.

You may be right as a couple of others have suggested it on other forums. Kind of a hard one to test so I ordered one from FindItParts. Thx.

[RLS7201]

If you have yellow turn signal lenses (5 wire system), then the brake lights and turn signals are on different wires and the brake light circuit does not go through the turn signal switch. Other wise you have a 3 wire system.

Richard

[CJW8]

ItsyRV wrote:
Does the brake and turn signal using the same "filament" on your coach or are they independent?

Here's where you can look up the wiring diagrams :
2004 Winnebago Wiring Diagrams
(not sure which model you have)

It isn't on those diagrams. It would be on the Chassis (Freightliner) diagrams.

[CJW8]

ItsyRV They use the same filament.

[ItsyRV]

Does the brake and turn signal using the same "filament" on your coach or are they independent?

Here's where you can look up the wiring diagrams :
2004 Winnebago Wiring Diagrams
(not sure which model you have)

[ROBERTSUNRUS]

🙂 Hi, it might be the turn signal switch. If using the same bulbs for stop and turn, as most vehicles do, I would check the turn signal switch. The turn signal switch cancels the brake lights so you can have a turn signal on while braking. Some early GM vehicles had a problem with the hazard switch not returning all of the way and preventing the brake lights from working. Either case would need a turn signal switch replacement. (now days, sometimes called a multifunction switch)