Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Temperature gauge

Temperature gauge on 1991 F150 pegged out to cold side–Truck runs OK considering age. what do i look for? All other gauges look fine

Try this simple little test: remove the wire from the sending unit, ground it to the engine & turn the key to run.

If the gauge moves to full hot, replace the sending unit.

If the gauge does’nt move, look for a break in the wire or a bad gauge.

I bet your temp sensor isn’t working. Same thing happened to my 01 Impala. Replaced the temp sensor, and it was mended.

The most common cause of a temperature gauge reading cold is that the coolant is cold. Does your heat work? Does the motor ever get all the way hot? Stuck open thermostats are much more common than failing gauges or senders.