Bizzare electrical glitch

[Piloter]

Just today I noticed that, with the lights off, whenever I push the brake enough to illuminate the brake lights I have all instrument/marker lights turn on as if the light switch was turned on to the first click, along with a loud relay-type clack from the cig lighter/transmission area. Once I lift my foot again and the brake lights go out, so do the other lights. This is repeatable, and will happen even when I don't have the keys in the ignition -- which also triggers the shrill tone when you have your lights on and the keys out.

The only thing I can think of that's causing this is the right rear taillamp assembly, last time I washed the car there seems to be a little moisture stuck in there. Would this be enough to cause this? What do I do? I figured I'd take it out tomorrow, take out the bulbs, put it in the oven for 15 minutes at 90 degrees to try and bake the moisture out...is that the right approach? Any better ideas?

[Bitter]

yea, sounds like a short to power, possibly between the brake filament and the turn signal filament.

[Piloter]

Ain't the taillight--I pulled the plug to that one and tested it, it's still illuminating the marker lights. I don't hear the clicking from the shifter area any more. I've had some sharp-edged stuff bashing around in my trunk for a while (50-pound rack-mount servers), are there any likely spots for harness damage down at about the level of the latch?

[96coroll]

i've got something happening on my car as well where i heard the same clicking from under the shifter. My highbeam is out on the driver side along with the two brake lights on the driver side and one on the left. I probally just have to change all of them at once. or at least i'm hoping i just haven't had the time.

[Piloter]

There seems to be no damage to the trunk wiring--I also noticed today that I have no cruise control any more. The light is on, the system doesn't blink it at me, it just won't set the speed. Are there relays in that area that could've glitched? Could this be a short in the brake light switch?

[94_Rolla_Guy]

check to see if when you turn the lights on if by chance the brake lights also come on, the cruise control will disengage if you press the brake, thats probably where your problem lies i had something very similar happen a few years ago, turns out the brake filament in one of my tail light bulbs blew and welded itself to the running light filament tieing the circuits together, making the brakes backpower the running lights or the running lights backpower the brake lights, thus causing the cruise to not work because the cruise ecu thinks you have your foot on the brake

[Piloter]

Yeah, you nailed it. One of the bulbs had blown nastily and filament-merged itself, the other bulb on the other side apparently had the filament wiggle when the current surge hit (they'll do that) and wiggled itself right into the other one as well, leaving no carbon scarring but just a tiny bit of whitish crud. I'll post pictures when I get home tomorrow so people know what to look for. Good call, I /like/ fixing electrical problems for less than $5. =) Thanks!

[Hiro Protagonist]

I've had the brake-light elements fuse together twice times in the past, although it's never affected any of the other circuits. Both times the brake lights would function normally if the headlights were turned off, and the parkers/tailights would work normally with the headlights on and brakes not applied, but as soon as you tried to apply power through both elements (ie braking with headlights on) the lights would cut out completely.

[Bitter]

Originally Posted by Bitter

yea, sounds like a short to power, possibly between the brake filament and the turn signal filament.