Could someone please tell me when the fans kick on and off (like what temperature, when the A/C is on, etc.) and what controls them (like CTS, fan relay, etc.)? Also, which fan is the primary and which is the secondary/auxiliary?

1990 IROC-Z 5.7

-Thanks

 

The left is the primary and right is AUX. Both are cut on by the ECM grounding the relay for each fan. ECM gets signals from the coolant temp sensor to turn on the pri at I believe 238F, and from the fan switch and the AC high press switch to turn on the AUX. I think at 243F or if the compressor pressure is greater than a certain figure and the speed is less than 40mph. If the AUX is cut on bc of AC then the pri will be cut on too bc of default mode. Two relays for the fans are right by the vapor canister on a Firebird, should be on the same side on a Camaro (P/S front by the radiator mount.)
That's what I know...

 

just incase you get ur left's and right's confused. i do sometimes

driverside fan = primary, passengers side is aux.

 

my diagram might help u out some. it gives the basics.

 

Ok, I found that the problem was the Primary Cooling Fan not kicking on. It will ONLY come in with the ALDL jumper and in Default Mode. It will NOT kick on when the engine temperature gets to 190 or whatever. I'm thinking it could be the relay... Where is it located at? Where are those 2 fuses located at?

 

The pri relay should be on the p/s right behind the radiator support. I don't know if you have the battery there or the charcoal canister. Both relays are there, the pri is on the side of the radiator and the AUX is on the fender. The fuse is in the fuse box and the fusable link is somewhere in the harness, you just have to look for it. If the AUX relay is good try plugging that into the pri harness and that'll tell you if the pri relay is bad.