Chevy S10 electrical question

Hello all,
I have a 2002 Chevy S10 with an electrical problem.
All manual, no electric mirrors, seats, locks, windows, etc. and no trailer connector.
It does have air conditioning and curse control.
V6, TBI, two wheel drive.
Never in an accident and only used for paved roads.
A few days ago, the rear lights came on and will not turn off, even when the truck is not running or even have a key in the ignition. If I turn on a blinker then that (right or left) bulb will blink on and off, but as soon as I turn off the blinker, the light goes back on. I pulled the connector to the break switch on the break peddle - no change. I then pulled the hazard/blinker unit from behind the glove box - no change. Looking at the electrical diagram in the Haynes manual, pulling these two things should cut off any supply of voltage to the circuit, but it does not. The manual only shows two fuses for the circuit but there are three fuses in the fuse block under the hood for these lights. I put the blinker and break switch back in and the lights started to work correctly - for a day. The problem came back. The lights go out when I pull the STOPLP 20 amp fuse, but then I have no turn signals or break lights. If I pull the LT TRN or the RT TRN fuse then the corresponding light goes out, but then I have no blinkers. If I turn the hazard switch on then I hear one click and the dash lights for the turn signals come on and stay on. Every once in a while the problem will go away and everything works correctly, but soon comes back.
Any ideas what I should check next???
Thanks,
Chris
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So it is as if the brake pedal is always pressed in?
Might want to check the brake pedal brake light switch. Be aware that there may be two or more switches which go to different things on the brake pedal. Such as the "curse control". (I need one of those! :-) )

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42 wrote:

harness has a short somewhere.
If you pull the harness to the MFS and the light is still on, your wire harness somewhere has a short. Your almost going to need factory wiring diagrams or a lot of luck to figure that out. look for things that look burnt or warped.
bob
bob
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You can get a GM factory service manual set at helminc.com. The complete set of books comes with electrical diagrams for *everything*.
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42 wrote:

Actually there are closer to 14 fuses involving those lights! 4 under the hood, then the individual circuit fuses for each light....
Probably the multi-function switch in the column. Stop lamp fuse sends power up through the switch and out to the lights through the brake switch. It also can short internally and send power to the lights like you were turning on the 4 way flashers. BUT because of the short they won't flash because the flasher is not in circuit.
--
Steve W.

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Thanks bob, bill and steve for the replies so far.
The MFS is something I was thinking about a couple of days ago. I will look into the steering column today to see how hard the MFS is to get at. Yes, I know not to mess with any yellow wires which connect to the air bag.
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42 wrote:

The short answer is It's a BIT%^ to get at....
The easy answer (and cheaper as well) Go to car-Part.com. Find a yard near you that has a complete column in the proper color and swap the entire thing. Cheaper, faster and FAR FAR easier....
--
Steve W.

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Hi!

That last option intrigues me. ;-)

Many of the lights are controlled by relay, so you could have a relay that's sticking.
But you might also want to make sure the lights are properly grounded. Messed up grounds will cause bad electrical behavior, and the ground for these lights is subject to rust or degradation.
William
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wrote in message

Thanks William, I've checked some of the ground points that I could find. I'm not sure which relay would control the lights since none are shown in the Haynes manual or inside the cover of the fuse block, however, much of the truck is a little different than the manual so there could very likely be a relay in the circut some place.
Yes, it has "curse" control, I got that aftermarket, to keep the kids from using bad words. It also has cruse control.
Thanks
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Did you make sure that the brake peddle lets the switch button come out....sometimes they can hold the button in.I 've had that happen a few times before. Bobby
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Yes, I actually removed the switch from the truck, still the lights would not go out. I even connected the switch to the circuit with the switch opened up so that I could see the contacts and manually open and close them, still the lights would not go out.
I'm starting to think it is about time to take a trip to the mechanic.
Thanks
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One place to pay close attention to for chafed wires is where the wirebundle runs between the gas tank and the bottom of the truck bed.
I had a fuel pump changed a while back, and the mechanic wound up chasing a tail light and blinker problem for 2 or 3 days.
HTH, Mark
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