Hello. I just picked up a 1987 camaro 305 tpi. The cooling fan wiring harness was butchered and the a/c has been removed. I've since purchased a new cooling fan wiring harness on eBay. Previously only the passenger side fan was coming off and on because of the way someone had wired it. Now I've got the cooling fan harness back to factory and their were no splices on the wiring harness the cooling fan harness connects to. Every thing matches color for color. With the new cooling fan harness the driver side fan is always on. I've found so much mixed information on the web. My understanding is the driver side fan should come on by way of the ecm and temp sensor when temperatures reach about 220° F. I've also read that on the v8s, if the ac is removed that there is a pin on the ecm that would need to be grounded. Can anyone elaborate for me? If this information is correct? And what pin needs to be grounded? Thank you Joe.

 

This for an 89 but may be close... from what I understand, the passenger side is the "Heavy Duty Fan" and the driver's side is the Primary. I bought an inexpensive thermostatically controlled switch from Autozone ($17) and had it ground the AC Pressure switch circuit whenever my setpoint temp was reached easy to tap the grn/wht wire on the Heavy Duty Fan Relay. Both fans come on, both fans go off. Works great.