My 1997 Civic's battery was dead about two weeks ago on a Thursday as if I had left something on. However ALL switches were OFF. Someone from a garage jumped it on.

A few hours later the temp gauge shows it is very, EXTREMELY hot, even if I only drove it for only 5 minutes. I take the car to my regular mechanic who says the "jumping it may have damaged the thermostat." He changed radiator, thermostat.

I take the car on a long drive from New York City to Jersey, and about 100 miles the radio pops, then the odometer crackles, and both give a puff of smoke. The car dies with smoke coming from the battery and the under-the-hood fuse box. But NO fuse was tripped.

I take it to a garage, who say "the PCM is gone, you need a new one." When I go to pick up the car, they say it was the alternator which was overcharging, putting out almost 20 volts. They put a new one and a new battery but left the old PCM. I start the car, again, the battery is completely dead. They jump the car with cables, tell me it will reach home. I find the odometer and speedometer are not working, they refuse to repair it. Also the wipers do not work when I turn them to the first setting, but work on the higher speeds.

I get home, able to turn it on and off several times within about 30 minutes each with no problems. The next day, again the battery is completely dead, this time a new battery!

Questions:
1) Why would a battery be completely dead from ONE day to another, with ALL switches off, yet not discharge when turned off earlier?

2) Why would both the odometer and speedometer be dead in this case? Aren't these a mechanical linkage?

3) Why didn't the fuses trip??