Brake Light Ckt Help?

[ItBites]

All,

Please help, cause I hate electrical problems. I am sure I could find the problem with enough undoing harnesses and testing, but I thought one of you folks might know right where the problem likely is.

Here are the clues:

My Brake lights do not work. Additionally, the rear Hazard flashers do not work (but the fronts do, so I think the hazard flasher unit is OK and I would also think the hazard switch in the column is also OK?).

The rear turn signals (as well as the fronts ) do work and at the rear use the "bright" filament (1157 bulb) that the brake light and hazard flashers would use if they worked, so the bulb is good (I also ohmed the bulbs - both - just to be sure). This also indicates the ground at the bulb socket is good. Also the "dim" running light filament works, so again the ground is good at the light socket.

The brake light switch under the dash has 12+ volts to it on one side and not on the other when the pedal is not depressed (should be correct - no volts from the switch to the brake light). The switch has 12+ volts on both sides of it when the pedal is depressed, which should provide power to the brake lights - ??except something is wrong between there and the brake light??

WTF is in the path after the switch at the pedal??????

I am thinking the turn and hazard flashers have to be in the loop somewhere since the brake light goes intermittent when turn signal or hazards are invoked? but not directly in the loop. Here is where I lose understanding:

I pulled the hazard and turn flashers and they are of the two-prong variety, so there are not multiple circuits thru them and as I said before the turn signals all work and the hazards in the front work, so I think the flashers are OK. I also ohmed them out and the each had about 45ohms impedence, which is relatively low and should allow volts to the brake lights if it normally goes thru one of them, but if it did, you'd think it would excite the bimetallic switch and then flash, so it cant just run thru the flashers on a normal basis, so how does the turn signal interact?


The reason I am looking for a device in the circuit (rather than a broken wire) is because the hazards AND the brake lights do not work, so the clue is that something common to those circuits is bad.

I also suspect the wire to the light from the dash region to the "bright" filament is common for the brake light, the hazard, and the turn signal (which works). If this wire is common (since it goes to the same filament), then the problem lies somewhere between the brake switch and the combined line running power to the "bright" filament. This is an assumption, but the turn signal does work.

Anyhow, if any of youse have any insight, I'd be mighty beholden.