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Thread: A/c problem..help!

  1. #1
    Potential Tuner
    Join Date
    Jan 2018
    Posts
    1

    A/c problem..help!

    Bought a Yukon with a bad motor.i put a motor together with a stage2 btr cam..not sure if the a/c was working before or not..it?s a 2004,I converted it to electric fans with oem 05 fuse block and wires,pinned it to the pcm correctly like factory would..had it tuned,and just cannot get the a/c to work..I took it to a GM dealer,they put the scanner on it,all pressure sensors and switches are reading correct,pressure is correct in the system..the tech tried to command the a/c on with his tool and was denied..the pcm will not trigger the relay to power the a/c compressor..I can jump it at the relay and the compressor comes on..all fuses relays have been checked.ive changed the pcm and had it retuned...can someone help me..I have the tune file if someone wants to check into those settings,I just can?t open it because I don?t have hpt

  2. #2
    Check your ac fitment and fan type parameters is the systems tab. It must match which ever ecm configuration you are running. For instance if you have a p59 pcm it communicates to the hvac controller through serial data in most cases. So the system setting has to be in that for them properly talk to each other. As well have the advanced hpt view open helps with verifying all the setting of what the pcm is determining it's commanded states. Although 03 and 04 in most cases have the correct (p59) pcm to do a direct electric fan conversion. It isn't completely plug and play, the settings have to be brought into a range the pcm can see since with a mechanical fan it did care to look at them. The settings have to match what 05 and 06 have, comparing a stock 05 06 file with e-fans makes this easiest. Hope this helps.