In trying to get my AC working, I noticed that my fan was turning slow very when it was engaged.

Its a single fan car still, and my PCM is wired out of of the high speed relay control (no wires connected to the low speed relay control).

I checked at the relay and I'm getting 12v on the 86 (D) and 30 (E) terminals. With the fan unplugged, I get 0v at the actual fan plug on the thick black/red wire when the car is under 220 degrees. When it gets hotter than 220 I get a relatively small amount of voltage ... between .5 and 4v. The fan turns slowly at this point if I plug the connector back in.

If I disconnect the relay and jump directly from 30 (E) to 87 (A), I definitely get 12v at the fan connector and the fan operates at the expected speed.

I did get the PCM tuned recently to work towards getting AC enabled (changed AC input type to analog, changed AC fan disable speed from 0 to 90 mph -- see attached). All my fan relay troubleshooting was done with AC off.

I'm a bit at a loss here. I swapped the fuel and the fan relays. Fuel continued to work well, fan behaved the same. I bought a new relay for the fan, and it didnt help either. The only thing I can think of is that either I should run the low speed fan connection to the relay or the existing wire from the PCM to the relay is bad.

Any help is greatly appreciated.

Thanks

 

duplicate post.

 

Well positive momentum today. I wired blue 42 (low fan) to the same relay that the fan output was already wired to. At 210 degrees the fan kicked on full power.

After doing a lot of reading, it looks like my high fan output issue may be linked to the Air Recirc setting. I think it needs to be set at Fan #2 for pin green 33 to ground. Not sure what it is doing as configured (set as AC recirc as shown in the attachment above). I'll try to get it to the tuner this week to see if that fixes the high side fan.

http://www.performancetrucks.net/for...needed-539577/

Post 10 has some good information about the AC Recirc for anyone doing blue/green PCM swaps.

Thanks
Chuck