I have an 87 GTA 5.7L Automatic. Car runs great, I did just do a new 180* thermostat, I set the fan kick on for both ac on/off at 185 and off for both at 175*. What I can't find is a setting for the secondary fan. I know it comes on when the A/C is on or the car is at 236*, where is this setting? Can it even be modified? I am wanting them both to kick on at 185ish and off at 175ish. Are these "good" settings to run with a 180* thermostat?

Any help is greatly appreciated

RJMcEachern

 

I believe on third gens there is a secondary fan switch either in the cylinder head or intake manifold. It controls the fan independent of the ECM. If you want to lower the fan temperature, you'll have acquire a switch with a lower temperature and simply swap your existing one for the lower temp one. Pretty simple.

Now, in the later 7730 ECM's (90-92 MAP cars) there is a function allocated in the ECM for a secondary fan which I've taken advantage of for my 2 speed Taurus fan. But I had to run another wire into the ECM harness to connect up to the output terminal on the ECM . The 90-92 Camaros do not come factory using that circuit, rather they have the same setup as you. I'm not sure if the MAF ECMs even have that capability though.

 

forgot to mention it is a 165 ECM running the factory ABWT bin.

 

For the secondary fan to actually be controlled by the ECM, you need to splice a few wires at the ecm connector, I dont remember which ones but it will work after you do that!

 

Bingo.

It's in the passenger head between 5 and 7.

Dont set the fans to kick on near thermostat temperature range. If you have a functioning air dam, like you should, the thermostat will control the temp of the car in motion. Fans should be set to come on just after the t-stat range say 195 on 190 off

180* stat and aluminum radiator here, engine temp will bounce off the t-stat all day long even in 100*+ weather.