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Just bought a 68 Chevelle with an LS1 out of a 2002 Camaro SS. It is currently wired up to use a manually switched radiator fan. How would I go about restoring it to the factory thermostat controlled switch?
The PCM for the Camaro controls the fans. It's a pretty good system and recommended for use on swaps such as yours. Guys with trucks change to E-fans and get the PCM control working.
The LS1 fan setup for the F-body PCM runs both fans in series for low speed and in parallel for high speed when needed. The PCM has two pins that it grounds and these work a few relays that power the fans as needed.
If it's a 2-speed fan, and you want to retain the 2-speed functionality (which is recommended), buy a Volvo fan relay. It doesn't get much cheaper (~$25 on eBay) + easier (5-wire hookup) than that.
In the event you can't find the fan control wires and/or don't want to trace them back to the PCM, you can use a dual-temp switch to control low and high speed.
Wire hookup, from left to right:
OUT
2 - to fan high speed
1 - to fan low speed
IN
2 - to PCM fan 2 control (blue connector at the PCM, pin 28; wire should be dark blue)
1 - to PCM fan 1 control (red connector, pin 43; dark green wire)
08-24-2015, 01:52 PM
Wiring radiator fan 
