I have a 96 C2500 Sub, VIN "F". I keep reading about high idle when the a/c is on. Is this something the truck should do when the a/c is turned on? My truck does not idle up when the a/c is turned on. And at a traffic light or similar situation when the truck is in gear and stopped the a/c doesn't work great. If I rasie the idle a tad it works better. I have had it in to the local shop and all the pieces and parts are working okay and it is charged properly according to the technician. Is there a way to test this? Thanks for any help.

 

My bet is the compressor is a tad worn out much a new compressor would remedy that issue

 

I had the local shop I take it to check it in June. According to them it is working fine. I will have them check the pressures specifically next time it is in just to make sure.

I'll check the wiring diagram to see if there is such thing that would tell the ECM to increase the idle speed when the a/c is on. Could a worn fan clutch do the same thing? Maybe it's just a quirk I have to live with. Thanks for the help.

 

Fan clutch would not have anything to do with it I had the same issue with my 94 earlier this year put a new compressor,reciever drier,orifice tube,oil and freon and my nipples will cut glass when it is 90degrees out .

 

There is a high idle option you can gnd a pin in the PCM harness to achieve it but that is for trucks running the PTO.

How clean are condenser fins 6.5 rad stacks are notoriously crudded up inbetween rad & condenser it is a low pressure area and bugs/dirt accumulate there if you have never done a deep clean of this area and it takes 3 hrs minimum to do it correctly I would start there.