When I turn my parking lights on or headlights on my brake lights turn on as well. And When my lights are selected off like during the day, When I put my foot on the brake pedal to turn on the brakes my guage lights turn on and my parking lights turn on. Any idea what the hell is going?

 

Check for 'shorted' bulbs. My guess is a filament in one of your 1157 bulbs in the rear has broken and crossed the circuits of brake and tail lights. Find the bulb and replace it.... fixed!

 

Had the same prob. I had a blown tail light bulb that was short circuiting. Check your tail lights bulbs one at a time, and clean 'em all up while your there. There's a great chance that'll be it.

 

How can it be a 1157 that bulb is a dual filiment. Why would I need a dual filiment bulb when I have a seperate brake light bulb and a seperate tail light bulb. And when I turn my headlights on my tail lights don't turn on, just the brake light bulbs turn on.

I also replaced my taillights bulbs with 1157s and noticed the two contact metal strips in the taillight sockets was missing one contact strip. Looks like they had rusted off. So I am assuming that is my problem and I need two new taillight sockets.

 

We are talking about your 86 IROC, right?

Unless someone changed something on your car, the brake and tail lights use the same bulb. The turn signal bulbs are single filaments.

Yes, a 'shorted' socket will do that too.

 

Yeah I noticed that after I went back outside. Stupid error on my part. The new bulbs worked and the brake lights now come on only when I step on the brakes. The only thing I noticed is that the intensity of the brake lights when the headlights are on are not that big of a difference than the taillights. The taillights are a little dimmer but not by much. Also what kind of bulbs are used for the hatch tail light since mine is not working.

I still have the problem where even when the key is off and I step on the brake pedal the lights on chime comes on and my instroment guage lights and parking lights turn on. I am assuming this is due to a bad ground somewhere because whoever did the wiring job on this car sucks at wiring. Its worse than gettorigging a car. All the wires this person touched are not even soddered. Or even shrink wrapped. All they did was twist the wires together and on maybe 20% of the wiring he did was wrapped in electrical tape. This being said the other problem is with the headlight select switch/****. If you pull the **** to turn on the headlights and twist it sometimes the introment guage lights turn on and sometimes they don't.

 

That is a good assumption on your part. The grounds are the first place I would start looking since you still seem to have a backfeed problem and only a little difference in brake/tail intensity. After you check the grounds, get those rotten connections soldered (and replace that bad socket you mentioned earlier) and your lights should be good as new.

The problem with the dashlights and the headlight switch is a common one. It is a variable resistor that controls the current to the dashlights. It is really just a spring set in a ceramic heat sink and a paddle connected to the ****'s shaft just slides over the spring to adjust the current. Dirt, corrosion and hot spots all cause intermittent connection problems between the paddle and the spring. You could try taking out the switch and cleaning the spring and the paddle but, you'd probably be better off buying a new switch.

 

Figuire I re-awaken this thread. I tinkered around for about 2 hours looking for what is going on. I found a white wire spliced into the brown power wire for my LH front side marker lamp. I clipped it to see if that was causing the problem, Nope didn't fix it, I also found that I have a bad connection somewhere going from one side marker to the other. I wiggled the harness and the side markers went out and came back on when I wiggled the harness agian. I replaced the parking light bulbs hoping that one was shorted but that wasn't the problem either. So at this point I am thinking that this is not a ground issue but a crappy wiring job by whoever did the work on this before I got it. Anybody have any Idea what would cause the parking lights to come on when I step on the brake pedal>

 

13 years later from across the globe and this still answers the problem, thanks you just saved me a fortune.