Pontiac Repair: 1995 Pontiac Grand Prix SE, pontiac grand prix, temperature switch

Question
I have a 1995 Pontiac Grand Prix SE, both cooling fans appear to not be functioning.  The thermostat is working, the relays work when bypassed and both fan motors run when bypassed, however when together, nothing happens.  I have been wondering if it is the temperature sensor or temperature switch, both of which I can't not seem to locate or know how to test.  Any suggestions?

Answer
do the fans come on with the a/c does the a/c work? and the a/c clutch enguauge? the fan and or fan should operate when the a/c is on ,, are all the fuses good? not locate the fan temp sender, usually there is one sending unit for your light/and or guage, and one for the computer and or fan. if nothing less go get one for the fan at the parts store and find the exact match on the motor and replace it, make sure you have pleant of coolant in the rad and the system is full, once you find the right sending unit if its a two wire you can unplug it and jumoper the two wires witha paperclip, while the key in on, see if the relay for the fan clicks, if its a one wire momentarly use the paperclip and touch the other side of it to ground and see if it truggers too, if not you might have a loose connection on the realy or fuse, or a bad wire