On every thirdgen I have owned, the sensor in (coolant) the front is for ECM, sensor in the drivers side for gauge, and sensor in passenger side for fan switch.

My passenger side got burned off by the headers and is now disconnected, yet my fans turn on at like 230... And my guage works.

-- Joe

 

The one on the passenger side is just an auxillary (hard-wired) switch. Your ECM is turning on the fan based on the sensor in the front of the engine (CTS).

------------------
-Greg

'85 Trans Am - WS6,TPI:
Original owner, original paint/engine/interior, plus the usual bolt-ons

 

thanks thats very usefull.

Do you know of a way to check the fan switch and relay?

Also is it the fan switch or the sensor that controls when the fan comeon? and how hard is it to just wire a switch to turn on the fan in the head... and whats wrong with this?>

 

The fan switch is basically a ground that grounds out the fans when they get to the temp. rang of the fan switch. If you really want to you can hook up a toggle switch to the fan switch to turn your fans off and on. To do so groung out your toggle switch and run the other end of the toggle switch to the fan switch. Splice your toggle switch wire to your fan switch wire and you are done now all you have to do is flip the toggle switch when you want your fans to turn on. (sorry if this is confusing I explained this the best that I could)- Steve