1994 caprice wiring problem HELP

CHEFA2001 · Post by **CHEFA2001** » Sat Aug 31, 2002 10:27 am

I have a weird situation here, friend of mine has a 1994 carpice police package and after (or what we believe to be after) a removal of a specra remote mounted radio and a Maratrac radio with siren setup, the rear lights no longer worked...

I'll explain, the turn signals work fine, the reverse lights do not work, the emergency flashers don't work and the brake lights don't work....

When back flash is turned on, the brake and reverse lights work fine....

I checked the fuse (main panel inside car) and that certain fuse is not blown and there's no power coming to it....

I did not want to apply power to the one side of the fuse area in case I would damage something, but nevertheless, I am stumped...

I checked the other fuse panel under the hood, the max fuses or whatever they're called, all ok.

Someone else jerry rigged something to do the following:

Tapped into aux power @ the main fuse panel and bridged it into a wire bt the brake switch, so the car at least has brake lights....

I don't believe that there was or would have been any wiring interconnected with the old radios setups that would have made the rear lights cease to function, but since we don't know exactly when the lights stoppped working, we're @ a loss here.......

Someone mentioned that the fuse block was no good, but I think that they were just specualting and if that was the case we could have just cut the wire going into the rear of the fuse block for the rear lights and installed our own external fuse... (thatspecualtion was from someone who couldn't find any problem and had no clue why they don't work)

I know that this is not really a radio issue question, but since there are alot of people here who do work on p/p car instals, maybe someone has a guess????

Threeshot223 · Post by **Threeshot223** » Sat Aug 31, 2002 5:19 pm

Well, since you say the car was former police, I would check the wiring harness in the trunk. There should be a bundle of wired that runs into the left tail light shell. More than likely, you will find that the bundle has been taped/cut/spliced/crimped to hell and back. Since the de-installation process of most police vehicles is quite literally a hack job, more than likely the wires were cut.

It should be fairly easy to trace the problem. If the fuse is good, and there's power at the fuse, then there's a wire broken somewhere. As stated above, that more than likely area is the trunk harness.

CHEFA2001 · Post by **CHEFA2001** » Sat Aug 31, 2002 5:25 pm

hi, there's no power @ the fuse, and the backflash unit is still intact and operational. Nothing was cut. Since the backflash unit still operates the backup lights and brake/tail lights , I am assuming that somethign else is wrong such as a relay, switch, or?????

Threeshot223 · Post by **Threeshot223** » Sun Sep 01, 2002 7:49 am

Hmm....it might be your brake switch. Do the tail lights light up when you turn on the headlights?

CHEFA2001 · Post by **CHEFA2001** » Sun Sep 01, 2002 8:59 am

Hmm, not sure but I know that the wire tapped into the brake switch wire is feeding power to it now, so I will take it off and check it with a meter....

Would the brake switch though have any bearing at all to the reverse lights going on??

nmfire10 · Post by **nmfire10** » Sun Sep 01, 2002 9:14 am

Is there anything else not working?

CHEFA2001 · Post by **CHEFA2001** » Sun Sep 01, 2002 9:24 am

hmm, nope, just what I mentioned originally, The reverse lights, the tail lights, and the brake lights......and emergency flahers, "4 ways"
The turn signals work.

Threeshot223 · Post by **Threeshot223** » Sun Sep 01, 2002 7:16 pm

What do you mean when you say "back flash...and then they work fine"?

CHEFA2001 · Post by **CHEFA2001** » Sun Sep 01, 2002 7:48 pm

3shot, I'm sorry I should have been more clear, the back flash unit is an alternating flasher which sequences between the brake lights andthe reverse lights....

Almost like wig-wag for headlights, but in this case it alternates the brake and the reverse lights...

When this unit is on, (activated) the reverse lights and the brake lights work (operate in the intended flash pattern), however once the backflash unit is powered down, the normal operation of the lighs does not function....

Understand?

nmfire10 · Post by **nmfire10** » Sun Sep 01, 2002 7:56 pm

well, maybe that back flash unit is toast.

jim · Post by **jim** » Sun Sep 01, 2002 8:03 pm

On the GM B-bodies, there is a REALLY common problem of a wire burning up on the connector under the steering column that carries the wiring from the turn signal/hazard/wiper switch. There is a single white wire in the inline connector that burns up at the connector that causes this condition. I'd check it.

CHEFA2001 · Post by **CHEFA2001** » Sun Sep 01, 2002 8:09 pm

Hye JIm, thanks and can you tell me more about this wire, exactly what color is it, any striping, exactly what is does and where it comes from and goes to?

Tahnks and I don't believe the backflash unit to be the culprit since the backflash unit is the only thing that IS working, however I WILL remove it from the circuit just to rule it out...

Threeshot223 · Post by **Threeshot223** » Sun Sep 01, 2002 8:11 pm

Well, if the flasher unit is working, that indicates that the lights are getting power, at least to the flasher. Sounds like the flasher is more than likely miswired.

I'd remove the flasher, remove all the crimp connectors and such, and reconnect each wire to its matching wire, as though no flasher had ever been installed. The lights should work fine by then.

CHEFA2001 · Post by **CHEFA2001** » Sun Sep 01, 2002 8:14 pm

Hey, Should have mentioned that the vehicle has a full lighting package installed, and in addition to strobes all around, wig wag, backflash, etc..
The lighting package was in for 4 years and all worked fine, just recently the problem started, so I know the backflash is not miswired...

ANy other ideas?

FireCpt809 · Post by **FireCpt809** » Sun Sep 01, 2002 8:19 pm

I think Jim's answer would be another good place to look. I had a 94 caprice in with a problem that the Brake lights wouldn't wwork when the tilt wheel was in the middle position. It was the White wire in the black harness lust below the steering colum. Another possibilty is that the car had at one time had a "kill" switch for the brake lights. Maybe the butt connector that was used to splice it is bad. There is always the possiblity that the brake switch is bad at the pedal...

CHEFA2001 · Post by **CHEFA2001** » Sun Sep 01, 2002 8:21 pm

I'll check it out with a meter and get back to all of you...

ANyone know what I should see @ the switch, Ground or positive?
Does this drive a relay or go right to the lights?

I am not sure this is the issue as how would the brake light switch cause the reverse lights not to work?

FireCpt809 · Post by **FireCpt809** » Sun Sep 01, 2002 8:52 pm

12 + at the switch. The reverse lights are cut also with " kills" or "black out" Its a light green wire for reverse under the colum