Atomic

iTrader: (42)

Then lets give this one a shot

stroker87

iTrader: (6)

thanks Atomic

i jumped the clutch relay with a paper clip and the a/c compressor clutch engages and i get ice cold air, so i guess the a/c relay is not getting turned on i know its good i swapped it with the headlight relay

so at least now i know the problem is someplace between the relay and what commands it to turn on ...... this is a P.I.T.A.!!!!

Intimidator_ SS

I'm guessing this is your 04 Silverado? Did it work before? Or did you swap pcm? Or is it a ls swap project?

stroker87

iTrader: (6)

yes the 2004, this is a project truck but nothing has been done as of now other then E-fan swap under the hood 6.2 is on the back burner right now

i bought the truck in December and check to see if the a/c worked and it did at that time a/c clutch engaged

since i did the fan swap i'm going to check the connections at the pcm maybe i knocked something loose?

if there was a bad pressure switch or connection at the pcm when i jump the relay would the a/c clutch still engage?

Intimidator_ SS

Im having the same problem as you on my 2006 Silverado Lt it was a 4.8 4l60 with electric throttle body. I swap my engine to a 6.0 4l80 with a cable drive throttle body of a 00-02 Silverado and use a pcm of a 07 express van. I couldn't us the stock 06 pcm because it won't support cable drive throttle body or the 00-02 pcm because it won't read my 06 cluster. The only problem I had when I turn my truck after the swap is my fans wouldn't turn on hi or compressor turn on. My 06 truck came stock with the electric fans so I knew that wasn't the problem. I installed my 06 pcm and my fans will work on low and hi when I turn my a/c and I will get cold air. So I know the problem was my pcm I took my truck to my tuner and he set the hi fans to turn on since all express vans came with clutch fan and your 04 Silverado to . Your tuner can turn on your fans and has to calibrate your hi speed fan at a certain temperature and when you turn your A/c . If you're fans don't turn on hi it could stop your A/c compressor to turn on . This is only if you install you electric fans to your pcm

stroker87

iTrader: (6)

intimidator SS THANK YOU!!!

i googled the a/c-Efan swap and yup my pcm needed to be set to turn on the fans when the a/c is on

in HP Tuners the setting i changed are

system> A/C> under Hardware Recirculation Fitted option set to: AC Recirc & Type Fitted set to: Serial Cycling

I now have working A/C

thanks for the help guys!