# Car Fan Problems **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** ls, saturn\ **Created:** [April 10, 2011, 10:55pm UTC](https://community.cartalk.com/t/car-fan-problems/63572 "2011-04-10T22:55:39Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![mwkarrick](https://avatars.discourse-cdn.com/v4/letter/m/51bf81/32.png) [@mwkarrick](https://community.cartalk.com/u/mwkarrick)\ **Post date:** [April 10, 2011, 10:55pm UTC](https://community.cartalk.com/t/car-fan-problems/63572/1 "2011-04-10T22:55:39Z")
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. ---
**Author:** ![Joseph\_E\_Meehan](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/joseph_e_meehan/32/21_2.png) [@Joseph\_E\_Meehan](https://community.cartalk.com/u/Joseph_E_Meehan)\ **Post date:** [April 10, 2011, 11:08pm UTC](https://community.cartalk.com/t/car-fan-problems/63572/2 "2011-04-10T23:08:14Z")
Do you have any indication that the engine is overheating? I ---
**Author:** ![mwkarrick](https://avatars.discourse-cdn.com/v4/letter/m/51bf81/32.png) [@mwkarrick](https://community.cartalk.com/u/mwkarrick)\ **Post date:** [April 10, 2011, 11:09pm UTC](https://community.cartalk.com/t/car-fan-problems/63572/3 "2011-04-10T23:09:57Z")
no ---
**Author:** ![mwkarrick](https://avatars.discourse-cdn.com/v4/letter/m/51bf81/32.png) [@mwkarrick](https://community.cartalk.com/u/mwkarrick)\ **Post date:** [April 10, 2011, 11:12pm UTC](https://community.cartalk.com/t/car-fan-problems/63572/4 "2011-04-10T23:12:39Z")
i do know befor wen i turn the car off the fan comes on and now it doesnt ---
**Author:** ![BustedKnuckles](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bustedknuckles/32/25_2.png) [@BustedKnuckles](https://community.cartalk.com/u/BustedKnuckles)\ **Post date:** [April 10, 2011, 11:24pm UTC](https://community.cartalk.com/t/car-fan-problems/63572/5 "2011-04-10T23:24:22Z")
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. ---
**Author:** ![mwkarrick](https://avatars.discourse-cdn.com/v4/letter/m/51bf81/32.png) [@mwkarrick](https://community.cartalk.com/u/mwkarrick)\ **Post date:** [April 10, 2011, 11:28pm UTC](https://community.cartalk.com/t/car-fan-problems/63572/6 "2011-04-10T23:28:04Z")
how do i wired the fan to relay ---
**Author:** ![BustedKnuckles](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bustedknuckles/32/25_2.png) [@BustedKnuckles](https://community.cartalk.com/u/BustedKnuckles)\ **Post date:** [April 11, 2011, 2:01am UTC](https://community.cartalk.com/t/car-fan-problems/63572/7 "2011-04-11T02:01:16Z")
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.