The sensor in the thermostat housing is usually to blame.
Just a side note - have you removed the AC system? Are any fuses, including those for the AC blown?
The fan sensor is on the thermostat housing, I think facing toward the driverside fender. It has a rectangular black connector, with a spade terminal.
I dont think the 323 uses that particular sensor, check on Rockauto.com you can still buy them new for under $15, they have parts interchange there as well if you're going junkyarding.
Aftermarket part #'s:
STANDARD MOTOR PRODUCTS Part # TS113
KEMPARTS Part # RF22
ORIGINAL ENGINE MANAGEMENT Part # 8455
Hope this helps
-Rocket