ok, i have replaced the high pressure switch, and am getting power there. i am NOT getting power at the low pressure switch. i can manually bypass it all and put 12v to the compressor and it will blow cold and work fine, but the comp. is NOT cutting on itself. again, 12v at HPS, NOv at LPS...
A/C relay and fuse is fine... and i have bypassed the LPS and still got nothing... any ideas? or electric schematics?

Oh yeah, if you dont read the SIG, its a 2000 24v cummins...

 

wow... nothing in 24 views? kinda scary....

 

if my memory serves me right the pcm supplies 12 volts goes through the low first (i think) then goes through the high pressure switch and gets grounded by the control head in the cab so the pcm sees the request for ac if either switch is open the ac will not turn itself on thinking either too high pressure or not enough check pins in connectors and follow your way through system. be nice to see if the pcm is seeing the request for ac and not turning it on or if it is a switch or wiring problem on the request side. i presume your clutch fuse is good in underhood and that your relay is working?

 

see if this works, will be page 6

looks like it takes a few seconds to load then preivew it, or download and save


https://acrobat.com/#d=R349ikyMab6HZhfVJucUfw

 

yeah, fuses and relays are fine... ill check the pcm and see what i can find

thanks man

 

This looks like exactly what i have been looking for!!!
im gonna tear it apart today when i get off work and see what i can make happen....
also, wicked lookin dakota in your sig.pic.

 

problem fixed. didnt know there was multiple fuses.

 

thanks man, you should see my two cummins, glad i could help

 

id love to see pics!
and that diagram you linked to me (page 6) is exactly what i needed to fix it... i didnt reaize that it had 715 fuses for the darn air conditioner...lol

 

I have a 2007 2500 w/ the 5.9 cummins. I see this wiring diagram is for a 98 2500/3500, would it still be valid for my 2007?

I am having some AC issues. My AC clutch is not engaging. I have located the pressure switch that is located just above the compressor. I am not sure if that is the High Pressure or the Low Pressure Switch. I am not sure where the other pressure switch would be located, it is hiding from me. When I checked the wire terminals that connect to the pressure switch above the compressor I get 5V when I have the AC on and also when I have the AC off. When I plug the terminal back onto the pressure switch it will engage the clutch intermittently about three different times for a very short amount of time.

Hopefully I would like to find a wiring diagram for this pickup, and figure out where the other pressure switch is. Thanks for the help.