Cascade Crew

[Red Bird]

hey guys, the electric fan in my firebird is not working all the time, i noticed today my car got up to and passed 220 on the temp gauge, and it usually sits way below that, even in trafic, the fans kick on usually at about 190. i let the car sit and warm up and the fans did not come on,it got up to 225 but when i shut the car off and turned it back on the fans kicked on. its a 1991 LO3 firebird. is it a switch? coolant temp sensor? what do you think? the car sat over the winter. any one have this problem? any input would be appreciated.

[Leejo2005]

I'm gonna say it's either the coolant temp switch or the fan relay. The temp switch sends low current power to a relay which, in turn, switches high current power to the fan.

You could pull the temp switch and test it for continuity while running it through temperature ranges to see if it operates correctly.

The relay can be tested for continuity on the coil, the other "normally open" connection that powers the fan itself should read as an open with the coil de-energized and a short when energized.

[aaron_sK]

Al and I both also had trouble with a poor connection at the temp sender (passenger side head between the exhaust ports). In both cases it caused intermittent fan failure.

[Red Bird]

i am gonna test that sender out looks like its easiest to get it from under neath the car. where are the temp switch and relay?

[Al Hasse]

That temp sender on the passenger side head is the switch. The relay is up by the brake booster, which one it is I'm not for certain. You can ground the wire that goes to the switch, the turn the key on - the fan should run, then unplug relays until it turns off. Unorthodoxed, but it works.

[Red Bird]

thx al i'll try that