I had something similar happen to me. Replaced the voltage regulator 4 times
before I found the problem. Turns out that the gas gauge would short to
ground when I would hit a bad bump sometimes the gauges would peg and other
times they would just die. Your car may be different, but on mine the Fuel,
Oil and Temp all work off of the 5 volts that the instrument voltage
regulator puts out. If one of the gauges shorts out it will put 12 volts on
to the 5 volt circuit and peg or kill the other gauges and take out the
regulator as well. I had checked for shorts initially and didn't find any,
it was only when I wiggled the gas gauge did the short appear on the Ohm
Good article tech article on the subject:
"Oceandog" <email@example.com> wrote in message
> I have a 1982 Mustang, 3.3. Last week the oil pressure gauge and
> temperature gauge shot to the high side. Fuel gauge was fine. We replaced
> the temperature sending unit and the oil pressure sending unit. Nothing
> changed. Today we replaced the instrument cluster voltage regulator and
> the oil pressure gauge and temperature gauge immediately shot to the high
> side and so did the fuel gauge.
> We are at our wits end because we have no clue what to fix next.
> Can someone give me guidance?