Brake Tail Light Issue

[10Boomer]

Ok I need some assistance. Right rear brake light is bright all the time. No brake or running light 3157 bulb.
Steps I have taken so far:
1) replaced bulb, no change.
2) swapped bulbs, no change.
3) turned bulbs around in socket, no change.
4) checked tow plug on coach, didn't see any bad wires, everything is tight.

Now what?

[twinboat]

It's bright with no lights on or brake pedal pressed ?

Check for power wire in trailer connector touching signal wire.

If this happens when the lights are on, check the front light on the same side.

[10Boomer]

With or with out brake pressed. Left light normal.

[BrianGlenn]

Check ground.
Check socket for 12V at each tab.

[10Boomer]

Thx guys will do tonight.

[10Boomer]

Originally Posted by twinboat

It's bright with no lights on or brake pedal pressed ?

Check for power wire in trailer connector touching signal wire.

If this happens when the lights are on, check the front light on the same side.

Lights are on then press brake pedal, just stays bright.

[Woodman018]

My relay was stuck on one time and all my brake lights stayed on. I know you have a different issue but you may try tapping the relays while someone watches the light to see if it will go off. If it does you will know which relay is sticking. Just a shot in the dark but possibly worth a try.

Dave

[10Boomer]

Originally Posted by Woodman018

My relay was stuck on one time and all my brake lights stayed on. I know you have a different issue but you may try tapping the relays while someone watches the light to see if it will go off. If it does you will know which relay is sticking. Just a shot in the dark but possibly worth a try.



Dave

Relay mounted in front run bay?

[BrianGlenn]

Originally Posted by 10Boomer

Relay mounted in front run bay?

I thought of the relay, but the left works as designed, and the right is malfunctioning, even with bulbs switched around. More than likely an issue with socket or wiring AFTER the wiring loom split to the right tail light. I would be surprised if there are two brake light relays in the front run bay and two separate brake light wiring circuits run all the way from the front to the rear.

My thoughts.

Brian

[doublechevy]

does the right light function correctly as the right directional if not check if the flasher has gone bad.

[Captjake1]

Originally Posted by BrianGlenn

I thought of the relay, but the left works as designed, and the right is malfunctioning, even with bulbs switched around. More than likely an issue with socket or wiring AFTER the wiring loom split to the right tail light. I would be surprised if there are two brake light relays in the front run bay and two separate brake light wiring circuits run all the way from the front to the rear.

My thoughts.

Brian

I agree with Brian on this.

[William Willard]

Perry -- Just trade the darn thing in on a new coach & let someone else worry about the brake light -- Bill Willard

[l1v3fr33ord1]

Hmm.. I only have access to a Diplomat diagram of the same period. Something I hadn't noticed before, though- the brake light relay in the Rear Distribution Box has both the 87 and 87A contacts powered. The 87 gets its 12V from the BRK LT FUSE, and the 87A gets its 12V from the EXH BRAKE SOL. The brake light signal causes the switch between the two inputs. Interesting, but probably not germane to this problem.

If you pull the BRK LT FUSE (assuming one exists), does the symptom persist?

[10Boomer]

Originally Posted by William Willard

Perry -- Just trade the darn thing in on a new coach & let someone else worry about the brake light -- Bill Willard

Come On Bill I'm getting just right now.