I have a 2001 saturn l200. When I have the car running for awhile, the temp gets half way and the fan comes on, but then shuts right back off and will not come on again. Recently I have replaced the radiator fan, the fan module, and the sensor. How does the car fan work? We have had to add a switch to the fan to turn it on when we have to. Can you help please.
Do you have any indication that the engine is overheating? I
no
i do know befor wen i turn the car off the fan comes on and now it doesnt
How it works is sometimes simple. Typically, there is a dedicated sensor that reads the coolant temperature and simply sends a signal to a relay to turn on the fans. Recently, I’ve seen some models where the computer signals the fan relay(s) based on readings from the CTS and the A/C request. On your particular car, I have no idea which method is used. A wiring diagram should spell it out for you.
On some older models that I’m trying to keep running until they die, I have wired the fan relay to kick in whenever the engine is running. This may shorten the fan life, but is a cheap, easy way to keep it going.
how do i wired the fan to relay
You can take the switch they put in for you and find a source that comes on only when the ignition switch is on. One cheap one I can think of is the rear defroster circuit. But, you’re still going to need a wiring diagram to figure it all out.