Battery Dead problems of the 2001 Chevrolet Monte Carlo

The battery began failing (still had 1 1/2 years left on it). When everything in the car including security failed, by leaning on the passenger side seat I noticed the seat was "burning" hot. I received slight burns to both knees. Although black leather is hot in summer, the seat was extremely hot. Unplugging the seat began to cool the seat, but had apparently been on long enough to totally drain the battery. It was noted the battery was now sitting in acid which had spilled out of the battery caps. It is obvious the relay switch to the heated front passenger seat went on by itself without the hi/lo switch being on. The battery will now need to be replaced.

Since purchase of car with 34,000 miles in March of 2002, there have been several problems. Check engine light came on around 50,000 miles, had it checked was given the code for temperature sensor. Had sensor changed, within six months light came on again. When checked was given same code for temperature sensor so I had it replaced a second time. Now periodically while driving the temperature gauge will drop completely and when turning off the ignition the fan will continue to run. The only way to stop the fan is to either unplug the fan or unhook the battery. Randomly when trying to start the car it will not start as if the battery is dead, but the radio and all lights still work. Had this checked but no problems could be found. After waiting for about ten minutes the car will start. The only explanation I was given was that maybe the computer system thinks I am attempting to steal my own car. Then there are the turn signals, when you turn on the signal it will work for a few seconds then stop. The only way I have found to make them work again is to turn on the hazard flashers for a few seconds then turn on the signal again. There have been so many problems with this vehicle and with no warranty left it is rather costly and frustrating.