Rear Lights Going Haywire

[phipps]

I have a 2001 Chevy Venture and I noticed that whenever I press the brakes both turn signal indicators also come on. I didn't get a chance to actually look at what the lights were actually doing until tonight and they are going nuts!!

Everything works fine until you hit the brakes. When you hit the brakes the reverse lights come on as well. If you use the right turn signal and hit the brakes the brake lights and turn signal flash alternately and rapidly.

I'm guessing that I have a short somewhere, but where should I be looking? Is there a circuit board in the rear lights?

['97ventureowner]

That would be the first place to start. To see the condition of the circuit boards in the rear taillights. Water can get in there and short them out. Let us know what you find out.

[cjstew4]

Probably a short or ground issue on one or both rear circuit bds. (tailight assemblies). Make sure that your plug in harness connector hasn't shorted as well, as my 97's did. Both rear brake lights out, only third brake light on, as well as ABS and TCS idiot lights on. Cruise control not working either. You may have some or all of these symptoms, but it is probably the start of them. Pull the wire harness end off the plug to see if the middle contact (black wire of the harness) looks defective in anyway. If it looks a little burnt or its mating plug does, you have the famous short. If you buy new circuit bds (taillight assembly) only to solve your problem, goop weatherproof silicone caulk over the connection on both sides once you prove it works to prevent this shorting out from happening again. Design flaw by GM. Who would ever place any connection in the direct drain path of the rear hatch. The other option you have which costs about $5 is to label the harness wires that plug into the circuit board as to their location on the mating plug, cut the plug off the harness, attach connectors to each wire, cut down all 4 sides of the circuit bd plug about 3/8th to 1/2 in exposing the 5 pins. Be sure to clean off the shorted middle, thin prong/pin carefully. Attach the mating connector from the location markings you did earlier. Test the brakes, notice that your ABS/TCS dash lights are now out, and apply weatherproof silicone to the connections so that water, etc cannot collect at the harness or connections. The McGyver way, but my circuit has worked for over a year incident-free. email me separately at [email protected] to discuss more. Thought my ABS or Traction Control was on the fritz, but low and behold, only after looking this up on AF did I discover the problem and fix. If you go the new circuit bd route, the circuit cards I saw on Ebay recently were $27 US each which is a good deal. However, you still need to either replace the wire harness to them or perform the strip and add connector way I describe above. Thanks, Corey

[jaybo80]

I had the exact same problem about 9 months ago on my '98. Left side rear turn signal had a bad ground somewhere in the harness. I cut off the terminal of the ground wire from the connector at the light and installed a new 10 gage wire in it's place & screwed it directly to the sheet metal under the light. Make sure to take all the paint off of the sheet metal around the hole you drill and use a star washer if you have any to make good contact. I then covered the connections with RTV silicone sealer. I haven't had any problems after doing this.

Good luck

[demo_deven]

Same problem with my '01 Warner Brothers Edit. Had it in at the shop and they found a faulty ground. Worked fine for a cuple weeks andwent all haywire again. Now the reverse sensor only works when you put on the brakes, doesn't matter what gear your in. They also go crazy only when the headlights are on. Needless to say i'm going to do what jaybo80 said. 10 gauge wire.

P.S. A good tip to help your circuits from not going haywire, coat them in vaseline.