'nuther stop light question

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rmchrgr

rmchrgr

Skate And Destroy
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Alright, I have brake lights some of the time but only when the car is running. Key off, I have power up to the switch. Tail lights, hazards and turn signals all work. Fuses are good, replaced a few 'just in case' there was unseen corrosion but everything there is hunky dory.

I have a new TS switch on hand but everything else that goes through that harness seems to work, plus the brake lights work some of the time.

Anyone have any ideas? Should the brake lights work without the ignition on or am I wrong?

Thanks,

- Greg
 
The fuses are layed out in 2 rows. One is hot at all times. Horn , brake, dome light, everything else, in that row should work with switch off or on.
Sounds like you have a problem somewhere other than the signal switch.
 
RedFish said:
The fuses are layed out in 2 rows. One is hot at all times. Horn , brake, dome light, everything else, in that row should work with switch off or on.
Sounds like you have a problem somewhere other than the signal switch.
Click to expand...

But where? I have power up to the switch with the key off so that tells me everything is OK up to that point including the fuse box. (Nice bright test light I might add) Dome light works, hazards, horn are all OK. Plus, the brake lights work when the engine is running.

How would or what could change the condition of that particular circuit when the ignition is on?
 
I just remembered something. Hazard lights interupt brake and turn circuits.
hazard lights are interopted by those also . Depends on ignition switch position. I'd have to get a service manual out and refresh my memory on exactly how all that works but in that is your problem.
 
Well, I think I may have found the issue. There is high resistance on the ground side of the brake light switch which I think would indicate the wiring in the TS switch. I have 1 ohm on the white wire at the connector on either side. AFAIK, acceptable resistance is usually .5 ohm, anything more is considered high resistance. With the key off, I read 12V at the pink feed wire on the TS connector, (4th pin) which comes from the flasher.

My idea here is that battery voltage is slightly higher when the engine is running, like 13.75-14V. I'm guessing that little bit of extra voltage is able to overcome the resistance and power the lights. I read a similar amount of resistance with the engine on but that's when the lights work. I can't really come up with another explanation.

I also thought the brake light switch might be toast, but since the lights actually work when the engine is running, that would eliminate that part of the circuit from fault. Yes? No?

Guess I'm replacing the TS switch after all?

Can anyone corroborate this idea for me?
 
with the vehicle running you should have 14.6 volts not 13 V.....and approx 12 to 12.6 when sitting there engine off
 
I tend to agree with some of the other postings that your problem may be in the turn signal switch or the flasher circuit. I would tend to doubt the ground is a problem but it should be checked and it's easy to rule out with a simple jumper.
 
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