I have a 96 blazer that we hooked up the wireing harness on to tow a camper and now my brake lights won't turn off unless we take the fuse out, replaced the brake switch cause we were told maybe we blew that when we hooked them up but thats not the problem, any thoughts??

 

Since the brake lights won't turn off, you have created a continuous path of 12V through the bulbs to ground, regardless of the brake switch operation. If you did not use the plug in type of wiring harness to attach the "trailer plug", then I would systematically undo each wire that you attached to and see what fixes the problem. I assume you know that the Blazer has a trailer connection plug-in location tucked up under the rear bumper. You simply unplug the mating harnesses, plug in the trailer wiring connector, plug in the disconnected harnesses and wha-la you should be good to go. Good Luck with it.

 

ok so we unhooked all the wires in the wireing harness and still the brake lights stay on any other idea's??

 

The brake lights stay on even when the vehicle has been restored to the "before" condition?!? Now that's strange. I'm assuming the brake lights worked properly before you did anything with the trailer hookup. Is that correct? Do the brake lights work OK when a trailer is hooked up to the trailer lighting harness? Regardless, if the brake lights stay on all the time, there is a continuous 12V to the bulbs to ground. You have a wiring short somewhere in the vehicle. Have you checked the wiring for bare spots (caused by rubbing) or cuts in the wires.

 

Does the high mount stop lamp remain on as well? If not, then you mostlikely have a faulty 4way switch in the multifunction switch. This is a common problem with it typically causing the lower brake lights not to illuminate, but it can happen the other way around as well. Try turning on the 4ways and turning them back off to see if they even work.

 

Wait a minute, you said the brake lights won't turn off. Are you absolutely sure it's the brake lights. The bulbs are dual filament and you might possibly be looking at the Tail lamps being stuck on. What fuse did you pull to turn the lights off, Fuse #1 is Brake lights, Fuse #3 is Parking Lights. I'm tracing the circuits in my Haynes manual and see 2 possibilities for continuous 12V to the bulbs.

Does the headlight switch have any effect on the "rear bulbs" going on or off? The answer will eliminate a 12V path.

 

Yes the high stop stays on also, the headlights dont do anything to it, the lights come on when the key is turned on without the #1 fuse (break lights) they do go off whenI depress the break peddal. Also with the fuse in the lights are on and I cant get it out of park.

 

Definitely sounds like you have some crossed wires somewhere...

 

OK, I'm going out on a limb here. From everything you've described, I'm going to guess that you either have a problem with the Hazard Flasher being bad OR you have a broken Hazard switch OR the multifunction switch (which has the hazard switch built into it) is faulty. You say the lights go off when you press the brake pedal, which definatively says you have a 12V feedback loop through the bulbs which the brake switch now breaks. My money is on the multifunction switch being bad in the steering column. There are so many contacts and wires (24 wires) coming out of that switch that a broken switch (even partially) could easily be feeding 12V to where it should not be going at any given time. Disconnect the switch harness connector at the firewall connector and see if the brake lights behave normally. Anew switch is $175.00 +/- at Autozone and not too hard to replace (pull the steering wheel, open the covers, replace switch, put back together). Be careful around the airbag though. A Haynes manual describes the process rather clearly). Good Luck.

 

With the fuse in the lights work right but you cant get it to come out of park,take the fuse out the lights are on you can put it in gear put the fuse back in,with thetruck running the lights stay on but when you hit the breaks the lights are brighter, but when you put it back into park it wont come back out of park again.The only thing we did was turn the hazard lights on and then back off .