fan works only when the AC is on

[copteaser]

I just purchased an 86 GN. The car came with an after market dual fan. the only problem is that the fans come on only when the AC is on. Can someone help me fix this? Any ideas will greatly be appreciated. Thanks

 

[pacecarta]

if it runs with ac its running off the high speed fan relay circuit
the high speed relay is only active with the ac or the overheat switch under the throttle linkage
the low speed relay is ecm controlled ... check the low speed relay on driver fender

if your fans have a racetronix hotwired harness with two relays its possible one of the relays that runs off the low speed circuit is bad or the fuse for that relay supply is blown

 

[GNVenom]

The AC pressure switch also turns on the low speed fan, when the pressure isn't excessive. Switch has a gray connector and three wires, common, one for low and one for high. You can jumper that gray connector to make the coolant fan run on low and on high, to test the relays. I'd do that first, to see if the relays work properly.

If the AC enables the coolant fan, the relay is OK, so it's likely an issue with the ECM drive, ECM connector, wiring to the low speed relay, or programming in the chip that has too high a temperature setting on the fan circuit.

 

[earlbrown]

Since it's aftermarket, you can't assUme it's wired correctly.

That being said, look at the plug for the stock fan and see if that's all the powers the aftermarket fans. Try and see if there are any wires coming in that aren't stock like a secondary power source from a relay running straight to the battery.

 

[copteaser]

Thanks to all the replies, its is fixed thanks to you all...( I had to rewire the fans).. again thanks