I need a diagram of the cooling system for my 91 sentra. I need to locate the cooling fan relay and switch. My fans will not kick on even after idling for a good while...so please help!! I've been told where to look and I can't find them so I need to be shown...

here is for the 2.0 http://i28.photobucket.com/albums/c216/Boogieman142/2.gif

here is for the 1.6 http://i28.photobucket.com/albums/c216/Boogieman142/1.gif

as far as the switch goes, the pcm turns it on.

Hey thanks alot man...that was the thing that I was looking for!!!!
as far as the PCM?? I know what it is but can it go bad?? Can I check that??

Hey thanks alot man...that was the thing that I was looking for!!!!
as far as the PCM?? I know what it is but can it go bad?? Can I check that??

They sure do go bad, just like any other electrical component. The pcm uses a ground switch to turn on and off various components. To test it, Find the wire going from the pcm to the fan relay and hook a test light into it with the test light getting power, and the ground through the pcm. Leave the car sitting a while and the light should turn on at the time that the fan turns on. if it doesn't then there is a problem between the relay and the pcm.