can somebody tell me the basics of how to override the automatic fan switch on a 93-97 z28 to make it manually operated? I've seen kits for sale but they are around $50+ and I know it would be a lot cheaper to do it from scratch.

 

The fan on/off temps are controlled by programming in the PCM. For the 94-97 cars, you can change them with something like a Hypertech programmer, PCM editing software, or send the PCM to a mail-order "tuner".

If you do install a thermostatic switch, or a manual switch to override the PCM programming, you need to include a diode in the circuit to prevent the PCM from setting a trouble code for the fan power supply circuit.

Shoebox has a guide to wiring up a manual switch. Go to this page and look at items #4, 5, or 6.

http://shbox.com/1/schematics_wiring.html

You really need to add a "signature", showing the year, engine, tranny, and any major mods, so that people can give you the correct answers. Not all 93-97 features and tech solutions are the same.... they vary with the year of the car, tranny type, etc.

 

My car is a 93 Z28 w/ a six speed transmission