03-03-2011, 10:35 PM
My Ford T-bird/cougar Elect&Vacum trouble shooting manual on page 65 shows the primary fan as being the small 7 blade fan. Is that correct? If that is correct my next ? is are both fans supposed to come on when AC is in use?
03-03-2011, 10:35 PM
03-03-2011, 10:43 PM
The fan on the passenger side is the primary. The driver side fan is the AC fan. The primary should only run when the engine temp requires it.
03-03-2011, 10:57 PM
The EVTM is wrong in labeling the primary and secondary fans in the IRCM wiring diagram for sure. Only the primary fan (pass side)should come in for AC unless it is very hot out and the AC high side press exceeds 310 psi in which case both fans will come on for AC.
03-03-2011, 11:46 PM
I thought the Ford manual may have been wrong. So is the primary fan (pass side) turned on by the EEC internally grounding pin 55 the brown/yellow trace wire?
03-03-2011, 11:58 PM
Not quite..... the fan DOES NOT run when the EEC grounds the command wire. The pass side fan run when the command wire is NOT grounded and doesnt run when the command wire is grounded. My guess is this is a "fail safe" feature. If the driver in the EEC fails or the command wire is cut / broken, the fan will always run to keep the engine from overheating. Ths is done by a voltage inverter in the IRCM that controls the primary fan relay.
03-04-2011, 12:37 AM
What I'm trying to do is find a way to safely turn on both fans manually if I wanted, without damaging the EEC. As I'm undestanding it right now. They are energizes in different ways, correct? The EVTM shows the primary relay with the voltage inverter with a pink wire. Pink NOT grounded fan should run then correct (assuming EVTM diagram is right on wire coloring. Would the secondary relay work with command wire being grounded by the EEC then? Oh; by the way thanks for your input so for.