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Discussion Starter #1
Ok guys, I'm stumped.

My 96 Caprice had perfectly normal brake lights yesterday, and today, they stopped working. The lights are fine (checked on a separate voltage supply), but I'm getting no voltage from the brake pedal switch back. All of the fuses are fine, but with the mess of police-innovation wiring, I can't tell which fuse goes to the brake pedal switch to isolate where my loss of power is from. Anyone have any experience with this?
 

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If you have power coming into the brake pedal switch then the fuses are fine. Now after the brake pedal switch since our Impala's use the same bulb for either brake or turn signal the brake wire goes to the signal switch. So now then the most likely problem is in the turn signal switch unit on the column. Do the turn signals work correctly?
 

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Discussion Starter #3
Turn signals work fine, but I don't seem to have any power from the brake pedal switch itself. I'm going to try to check from the hot line to the brake pedal switch to a ground point on the frame next and post back when I have the results.

Edit: Yep, I've got power to the brake pedal switch. So, what next if the turn signals are working?
 

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Does the power transfer across the switch when the pedal is depressed? If not then the switch has failed. If power transfers across then look up inside the column at the turn signal switch.
 

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Discussion Starter #5
Power transfers correctly, with the old switch and the new switch. Seriously though? The turn signal switch? >.<
 

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Yes since it makes the "decision" whether to flash the bulb or leave it steady on. And all this is based on the position of the signal lever with or with out the brake switch on. Since neither side is working (brake lights) then either the wire from the brake pedal has fallen off the turn signal connector or the switch internal connection point has failed.
 

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Come to think about it I have seen one vehicle where the brake switch would transfer power for a DMM but not for the lamps. I found it by jumping the connector with the switch removed and lite up the lamps. Might try that.

Also does the 3rd lamp work on your car? Many ignore it or disable it. But if it had worked then recheck its bulb for it might be blown now and not light up when the pedal is pressed. (DISCLAIMER: the third lamp [one in the back window or on the spoiler] does not need to work in order for the standard brake lamps to work.)
 

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Discussion Starter #8
Ok, so it looks like I'm done for the night then; I don't have a lit garage and tearing apart the column to get to the turn signal assembly is not my idea of a good night time activity.

I'll post more tomorrow.
 

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Discussion Starter #9
Come to think about it I have seen one vehicle where the brake switch would transfer power for a DMM but not for the lamps. I found it by jumping the connector with the switch removed and lite up the lamps. Might try that.

Also does the 3rd lamp work on your car? Many ignore it or disable it. But if it had worked then recheck its bulb for it might be blown now and not light up when the pedal is pressed. (DISCLAIMER: the third lamp [one in the back window or on the spoiler] does not need to work in order for the standard brake lamps to work.)
Nope, the center light hasn't worked since I got the car. I plan on (eventually) replacing it with a Larson scanner with a switch in the ceiling console, but that's a trivial issue compared to actually having the car road-legal.
 

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Sounds like your saying you have power before the brake switch, but not after when the pedal is depressed. Wouldnt that just be the brake switch?

Also could it possibly be a bad flasher? When I was swapping out to leds I had nightmares. I would get the bulbs to flash once then itd all go dim.
 

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Discussion Starter #11
Ok, updating while @ work:

I have already placed the (still working) brake pedal switch, and that wasn't the issue. I have power after that to the turn signal switch. All other lights work, including turn signals. Aside from the HID upgrade (brake lights were still working after that, and have been for a while), nothing else has changed.

Tore down the panels from the steering column, removed the security plate, and plugged in a new turn signal assembly to test if the one in the car was bad. I still have no brake lights. Returned the turn signal switch assembly and now it looks like it's just going to be tracing a crap-ton of wiring... unless anyone else has any ideas if there's some other unit that the power goes through before hitting the brake lights?

In the meanwhile, I'm stuck borrowing a car until this is fixed. :bang: :bang: :bang:
 

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If you dont have one already it might be in your interests to buy a short finder (dunno what theyre actually called) Harbor freight, mac, and snap on all have them, hooks into the wire your testing, then you trace it with a handheld unit and if there is a short it will beep in the vicinity of the short. Can save hours of time.

HIDs would have nothing to do with it. Ive had mine in a month after I bought the car.

I still think the flashers may have something to do with it. Ive tried pretty much all of the available flashers for our cars and the only one that worked for me (all LED lighting and still had to make a load resistor) was the Bussman super heavy duty variable load. Avalable at blowreillys I mean Oreilly Auto Parts. Dont waste your time on the Tridons or the factory replacement BWD. When I used these I had no brake lights or turn signals.
 

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Discussion Starter #13
If you dont have one already it might be in your interests to buy a short finder (dunno what theyre actually called) Harbor freight, mac, and snap on all have them, hooks into the wire your testing, then you trace it with a handheld unit and if there is a short it will beep in the vicinity of the short. Can save hours of time.

HIDs would have nothing to do with it. Ive had mine in a month after I bought the car.

I still think the flashers may have something to do with it. Ive tried pretty much all of the available flashers for our cars and the only one that worked for me (all LED lighting and still had to make a load resistor) was the Bussman super heavy duty variable load. Avalable at blowreillys I mean Oreilly Auto Parts. Dont waste your time on the Tridons or the factory replacement BWD. When I used these I had no brake lights or turn signals.
Why would it be the flashers if I still have turn signals & hazard lights? Wouldn't it stand to reason that both units should still be good?

I'll look into a short finder, or whatever they're called though. Sounds like it'll save a ton of grief.
 

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A short tester will help. Also a good 12 volt test lamp, even a home made one will be helpful. I would test the power going into the brake pedal and then at the turn signal switch with a 12 volt lamp. Like I said in a post earlier I did see a switch that had power coming in and out but had internal resistance to the point that it could not provide enough amps for the bulbs. In this case I am wondering if you have sufficient current to power the bulbs.

I do not follow the flasher unit theory pointed out above.
 

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Wonder if anyone has a wiring diagram for your car that they can share. Your turn signal switch should have at least two power sources. One from the key on position and second form the brake switch when the pedal is depressed.
 

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Idk why either just saying this hapened to me while swapping to LEDs and when I swapped to electronic flashers it worked properly.
OK well I don't believe he has swapped the bulbs out to LED's yet so that would rule out the flasher unit.

Which means we are still back to insufficient power coming into the turn signal switch assembly. Might have the voltage but definitely don't have the currant to make the system work properly. This could be caused by a corroded fuse for the brake lamp circuit. BTW that fuse will be hot at all times and the turn signal circuit will only be hot with the key turn on.
 

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Discussion Starter #18
Late late late last night we found the source of the problem: po-lice innovations.

Found a broken line going to a relay stuffed under the rhino liner(actually, found several... and a hole in the floorboard. >.<), then traced it back to a split off section of wire coming out of the pins to the turn signal switch harness. Connected the broken line back to the wire it was originally supposed to connect to, and viola! Lights came on, and I died a little more inside when I saw just HOW MUCH nappy wiring those assholes did. :bang:

In the meanwhile, I'll be looking for a cheap econo-car to run back and forth to work with, while I shelf the car to redo the interior. Kinda wanna hit everything I can in one go, and the wiring inside just NEEDS to be cleaned up, along with that hole. Thanks for the help guys.
 

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I would remove as much of that stuff as I could. Seems like it will most likely cause more problems later if you leave the excess in there.

What put the hole in the floor? And how hard to repair?
 

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Discussion Starter #20
I would remove as much of that stuff as I could. Seems like it will most likely cause more problems later if you leave the excess in there.

What put the hole in the floor? And how hard to repair?
I plan on removing the excess wiring as soon as I can, and will be welding a new piece of steel in when I get the chance. I'm now looking for a POS stick shift car with decent MPG that I can drive into the ground for a daily driver, that way I can park the car and gut the interior and rewire everything correctly/cut out the rust hole.

As far as what caused it? I have no idea.... I assume normal Michigan weather, ie road salt. I'll take a picture of what it looks like under the rhino liner and post it up here tomorrow when it's light out.
 
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