Sorry if this is wrong place, or if its a simple problem, but I've never had it happen before. Not sure what caused it, so I'll go back a few days.

About a week ago, I installed a powered subwoofer system, and a cd player. The player/harness didn't have a remote wire, so I ran from antennae wire, didn't work past 5 mins, tried a speaker wire, power fluctuated too much, then tapped into the red wire and put an inline grounded switch with a 20 amp fuse, worked fine. A few days ago, the main speakers stopped working, but the sub still did. Over past 2 days, I've converted the sealed beams to H4 bulbs. Low beams worked without a problem. Today, went to install High beams (I have a 4 headlight system) and the connectors were for 2-prong instead of 3-prong. I bought 2 3-prong H4 headlight pigtails, and wired in the 2 parallel poles, whick I found a diagram showing were +12 and ground (I didn't wire the third prong because diagram showed it was for low beams.) Low beams worked, turned high beams on and all 4 were lit, couldn't get high beams to turn off. Drove to my mother's house to babysit my brother and sister after school. Tried to get the Highs to turn off again, they started blinking on and off... all 4 lights. I started the engine so I wouldn't drain the battery. The radio speakers started working again. I sat for about 5 mins playing with the switch, then popped the hood to try to follow the wires. I turned the engine off. Under the hood I heard a shaking noise, the coolant tank was boiling. It boiled over. When it stopped boiling out, I opened the cap, the coolant is still, but I hear a boiling sound in the radiator still. And its starting to rain.

What did I do/ what happened to boil the coolant.

How can I fix it.

Its an 84 GMC caballero with a corvette LT1 engine circa 1992-96, I just bought it on December 26, and have had many problems, replaced most fuses, all lights, and the bolts that held the upper control arm for the passenger side broke 2 weeks ago...

also coolant is muddy brown, should it be?

Whoa! that's one of the strangest things I've ever heard of! the problem with the coolant boiling and the brown color could be caused by electrolysis. I only suspect that because of the masssive electrical problem. if that's the case, pull the battery wires until you trace the problem. as far as the electrical problem though, I'm lost, but I'm sure someone can help. If you want more responses, this thread should be in the ELECTRICAL SYSTEMS forum.

There's no way you have enough current through the cooling system to boil the coolant without blowing the fuse or melting the wire. If it is using old Dexcool or someone has dropped the "stop leak" pellets in the coolant it will look muddy. Time for a flush.

Did you notice the temp gauge or warning light before finding it boiled over? Does this use the Corvette electric fans? Those could be affected by fluky wiring. Maybe the fans couldn't come on, and/or the gauge is not functional due to wiring problems.

If I understand your post correctly, you turned off the headlight switch and the low and high beams remain on? Are they blinking quickly, or slow? If slow, it sounds like the headlight breaker is tripping, then resetting and they come back on.

I would start backtracking, put the original headlights back in and see what you have.

I did catch one thing in there. You say you put 3 terminal bulbs in place of the high beam bulb. This is wrong, in a 4 light system the low beams bulb have 3 terminals only. Yon need to get high beam bulbs in there, 2 terminals.
This makes me wonder how many other small electrical mistake you have made alone the way. You need to back track and start undoing what you have done.
The coolant problem is more then likely unrelated. You let it idle a longer then normal time and it overheated. Get the system flushed have the radiator checked, most likely gummed up and replace the thermostat.
Mike

Your Alternator is weak and eventually it's going to smoke, well OK, its not going to provide enough power out. You have a bad ground somewhere I'm thinking it's under your dash, that is why the lights are blinking.


Good Luck

Flush our the coolant, fix the ground and buy an Alternator for a 86 Caviler 2.8L V6. That will at least give you a Alternator that has a 95 Amp output. Stock rating and it will fit you may have to change the pulley but that should be it.