burning up alternators

My daughter has a 1997 Grand Prix GPT. It has everyone stumped.
The problem started with her car not having any power. If feels like she has her parking brake on. All the dash lights would either be blinking at her or no lights at all. Would take the battery cable lose then put it back on and it would run fine for a while. Got it to a mechanic and he checked ground wires and checked the alternator and said that it was bad so he changed it. Since then he has replaced about 4 of them in less then 2 weeks. Car runs fine for a short time (2 to 12 hours) and then does the same thing again. The battery is only a year old and he says it checks out good but I think we will take it back and get a new one just to see. Everytime he puts a new alternator in it it charges at 14 then all of a sudden it is charging at 17. He even added some extra ground wires. Still no help. She did have her thermostat replaced in November and her low coolant light has been coming on every now and then but the lever is good so I think that sensor is probably going out. But now when her car feels like the parking brake is on when she drives it, her car is over heating. Mechanic will take any help.

Anyone have any ideas.

it feels like the parking brake is on because the alternator is at full charge which adds a giant drag to the engine... this also will up the voltage to 17 in some cases. either something in your system is drawing way too much power or voltage regulator needs replacing.

let us know what you find out. my 96 gtp does the same thing.

check your underhood relay center for corrosion on the bottom, and remove relays one at a time to see if one is shorted. Also, check the battery jump post for corrosion or a power wire rubbed through causing a dead short.