What is wrong of thermost gauge is not working on 1985 Chevrolet celebrity cause fan is not working proper?

Answer 1

1985 Celb with the Pontiac 2.5L4 Iron Duke. The one wire switch that brings in the fan relay is mounted in the head, Or in the upper radiator hose connector near the head. The thermister that drives the guage/overtemp light is in one of the two forementioned locations. I can't remember one from the other, But it does not matter. Remove both wires from both switches. With the wires open the fan should be off, and the gauge should be low. Now ground the wires the fan should be on, and the guage should be high. If the gage deflects from hi to low with the wire opened and grounded, But does not work in normal operation, Replace the switch. If the fan does not come on and off with the opening and grounding of the wires, Then look into the fan relay, fan fuse, or fan motor. A bad thermostat will overheat an engine! The thermostat lets the water flow @ 195 deg F. The fan starts @ around 210 deg F. 210 is to hot for my likes. So on my 1986 Celb with 350,000 miles the temp switch is jumperd out and the fan runs all the time the key is on. My 1985 with 200,000 miles is the same way! I did a little work on my 1985 Celebrity today, So I check the location of the temp switches. The switch that turns on the overtemp light is mounted stright up in the head (right-front side of engine). The switch that starts the fan motor is below the first one @ at a 90 deg, it also has a round electric connector pin. Where the first one has a flat electricial connector.