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AC compressor won't turn on

15K views 9 replies 5 participants last post by  talltail  
#1 · (Edited)
I have tried to find the open circuit on this thing with no success. I have to jump the relay to make it engage. I am at a loss and need a kick in a different direction before I tear the dash out if anyone has any ideas I would greatly appreciate any and all help.

I have had the pressure checked and it is OK. I did just change the actuator and I hear it working. I read somewhere that there is a reset procedure but I'm not sure if it applies to my truck.

Thanks for having a look!
 
#3 ·
When I first bought my last LB7, the AC wouldn't come on. You had to hit the relay with a screwdriver, which kicked it on. I replaced it for $25 and it's worked great ever since.
 
#6 ·
The ECM's on these trucks are not prone to failure, but I have seen cases where the ECM failed and would not kick on the AC. Just had a customer with this issue on a shop truck.
 
#10 ·
I took the relay out and crossed the 87 & 30 terminals and the compressor clicked. I did try to use a different relay but no joy.


Have your batteries load tested - funny things happen when a battery is dying..

I haven't had them load tested. The truck turns over without any hesitation. I know that doesn't discount them but I have had a bad battery and remember how the truck acted. I will go and have it done this weekend just for one less thing it might be.
 
#8 ·
Have your batteries load tested - funny things happen when a battery is dying..