I have a stupid question about the dual fan setup. For the 3 wks i've had my '88 IROC LB9 the fan has stayed on when the ignition was on. I figured out is was getting a constant ground. My fan went out about 2 days ago almost making my car overheat. The still had ground and power. Long story shorter, I replaced the fan, ECT, and ECM. Now my auxilary fan doesn't turn on until 240 degrees, which is way too hot. When is the primary fan supposed to come on. Any guesses why mine now doesn't come on. Thanks for any help you guys might have.

 

The primary fan(driver side)will turn on at 230 degrees. The ecm and the coolant temp sensor(sensor in intake)work together and control the primary fan. The secondary fan(passenger side)will turn on at 240 degrees. The secondary fan is controlled by the cooling fan switch located in the passenger side head and the AC high pressure switch for AC operation. The secondary fan(pass. side) will only turn on if the primary fan(driver side) fails to turn on and the engine temp reaches 240 degrees, or if the AC system is activated. These should be the only times the secondary fan will turn on.

 

Thank you very much for your response. I was worried that something wasn't right. I just replaced BOTH my cooling fans, aux temp sensor and ECM. The driver's fan turns on about 230 degrees so i think its working right. My concern was that 230 is way to hot for these cars. But if you tell me thats when their supposed to turn on then i guess i'll go with it. Thanks again.

 

Our cars are designed to run hot. Its suppose to be for the best emmisions, performance and fuel economy. My post is the way my iroc is and everything I have read is thats what the factory settings are. 230 degrees for primary fan and around 240 for secondary fan if the primary fan fails to turn on or if the AC is turned on.