Overheating when i turn on the head lights temp go,s up when i put it in park and pull the ebrake temp go,s down

Sounds like head gasket again, but may be more serious this time. Overheating is not something to take lightly.

Pull plugs. crank. Water come out of cylinders? Head gasket. Possible cracked block or head this time, too. I'd be looking at a replacement engine.

most cars, the brake light comes on for many reasons.
4 or more, ebrake suck on, low fluild levels and catastropic brake failure.
key on , the lamps are in test mode. ebrake off , lamp off or its and error.
now temperature.
is it real> ? can fail in many ways
1:loose wire at sender
2: air pocket below, thermostat (look down rad cap hole dead cold
is the RAD full and burped of all air. ? if not bingo)
the temp guage hates air, it can not reAd Air temps,

The light can stay on for other reasons other then the park brake. Things like low fluid level in the master cylinder and defective master cylinders make it come on. Of course the park brake switch is also a common reason. Check the park brake switch for damaged wiring or other issues first.

when you open door does over head light go on? it thinks it fuse 11 its underdash if its good then you just need someone to help out step on brakes put ebrake on and try to shift out,
thats if the fuse under dashes is good

you can not turn the daytime running lights off,,,the only way is to put in park or pull ebrake, but they are just the regular headlight bulbs running on a lower wattage,,so you cant remove them

If you have the day-time running lights, you will have to find the fuse and pull it. They make these daytime running lights because you get a 10% less chance of an accident. (supposedly)

I fixed mine!! First check your ebrake switch by starting your vw and putting the ebrake on. If your daytime running lights stay on when the ebrake is engaged, its NOT the switch. Stay with me here. Turn vw off and pull fuse number 5. Mine was blown, but the legend only shows a pic of a book with an exclamation point. Meaning the book will tell you what it is, BUT IT DOESN'T . I replaced the 7.5 amp fuse and voila, victory. If it is not number 5, pull every fuse one at a time and inspect them closely. Do not assume, check each one. That is how I found mine after I bought and replaced the $10 switch. Running lights stay on because the switch is not being acknowledged, not because it is bad. I searched every forum I could find on this and there were no answers to this problem anywhere. So I am posting so there is an answer out there. What put me on the right track was the running lights staying on when the ebrake was engaged after I put in the new switch.

sounds like you have burnt through the insulation of two or more cables and they are fused together in the loom .Start looking from radio back

Your Buick is a 3.8 liter, and probably the best engine ever built. But as all good things it has a few flaws.
It is a aluminum block, that doesn't do well at all with heat, yet at -03 f. I would be more concerned with it freezing. Again a problem with anything aluminum.
The problem I have found is that the heads will crack and the dieseling you describe is common of a 3.8 with a cracked head. I would pull the spark plugs, if it is dieseling it has to have water on one of the cylinders. Pulling the spark plugs will tell wich one. and also check for faulty or blown freeze plugs in the block. They may just be pushed out a little.

Have you tried the actual wire connection there could be an interruption there, if you happen to have a multimeter then touch it to the ground (black wire) and each of the other ones in turn.

Also check that your ebrake is'nt stuck because if you have the ebrake on even the slightest bit then it will keep the running lights from being on. I know because I use it sometimes to play with the lighting effects.
Easiest way to make sure is to pull the ebrake with the car on and see if the ebrake lights up on the dash. if it doesn't then the dash light is just burnt and try the running lights holding the ebrake pressed as close to off as possible. if that doesnt do anything the line might have to be loosened to turn it off.