I am going to post current conditions about my rear driver side brake light...

both tail lights work
both rear turn signals work
passenger side brake light works
driver side brake light DOESN'T work
Hazard lights do not work (all four DON'T come on or flash)

I cannot locate the "hazard" flasher. I am told that it is either one of two places: backside of the "turn signal" flasher on the fuse block, or on a bracket under the dash board. Please correct me if needed.

I understand that the dual filament bulbs cannot be reversed in the socket, but I think they can. Operation of the bulb doesn't change when done so. So I switched the bulbs from the passenger side to the driver side; same conditions exist. The problem doesn't move to the passenger side.

I don't think that the continuity needs to be checked for the driver side problem because both filaments are functional, the tall filament is active for the tail lights, and the short filament is active for the turn signal and the brake light (only the brake light doesn't work).

I tried reading the scematic for this wiring and it looks like the rear brake circuit goes thru the turn signal/hazard switch... if this switch is bad, and it does effect the brake lights, why only the driver side?

HELP!

 

It would have to be the turn signal switch. The turn signals and the brake light circuits use the same filaments and wiring from the turn signal switch all the way back to the brake/turn lamps. So if your turn signal works in the back, then that means all the wiring and the bulb filament is ok.

The turn signal switch is pretty complicated inside. When you hit the brakes, the brake switch sends voltage to the turn switch which sends the voltage to BOTH rear brake/turn lamps. While this is happening, and you decide to operate the turn switch, it will disconnect the voltage from the brake switch to one bulb circuit, and re-connect the bulb to the flasher circuit, so the same filament that was on solid for braking, will now blink for turning.

 

It's only the TS flasher that got moved off the fuse panel & into the dash (so you could hear it better); the hazard flasher is always on the backside of the TS flasher location.

But I agree totally with Franklin - it's in the turn signal. This is the PITA part that controls the taillights & front blinkers, but the fact that the Hazards don't work suggests it's the whole switch that has problems. They're not difficult to replace, but from Ford they're ~$120 (last time I checked).

 

I was able to find the hazard flasher and there was no flasher connected. So I added a flasher and the hazards now work but the driver side rear hazard/brake still is not working. The turn signal still works as normal.

Someone please confirm again that my turn signal/hazard switch in my steering column is the problem, before I rip into it. I also am pointing in that direction.

I appreciate the reply's ! Thanks alot.

 

I would check the filament of that bulb first.

Take it out and give it a little flick with your finger to see if the filament vibrates.

 

It's a pain, but you can probably repair the switch without replacing it. Just be VERY careful as you disassemble it - the plastic is brittle and breaks easily, and there are a few small parts that have to be reassembled EXACTLY right. I don't think I've ever seen instructions on how to do it, so just use The Force.

 

DeHamma,

Did you ever find the fix to your brake light issue. I am having basically the same problem on the passenger side.

73 SCS

 

Yes I was able to fix the problem... replace the turn signal/hazard switch in the upper steering column. Everything is fine now.