Hey guys back with another question and upgrade for my p38. The old compressor which I have just rebuilt is a total waste of time, so I am replacing with a Viair 350c. It has a 100% duty cycle compared to the OEM 15% and moves 1.4cfm@0psi compared to the OEM's 0.4cfm@0psi. One problem I saw on landrovers.net is that you need to ground the thermal sensor wire from the wiring harness to fool the eas cpu into thinking the switch is working properly; does anyone know if this is literal (Just ground the wire) or do I need to do something special? Thanks ahead of time guys.

 

I believe just grounding the thermal sensing pin on the connector does it. To be sure, find the thread on how someone else did it. I read it and looked at the pictures of the connector I just can't remember where exactly I saw this. I found a youtube video that might be useful: This video trouble shoots the pump and the sensors. It also shows the connector pin out as well. Give it a look.

I have seen brand new OEM pumps that sell for about $100 US more than a rebuild kit; they are a direct fit as they are made for the P38.

 

Check RangeRovers.net. There is a great thread in the p38 tech sticky section about this very issue.

 

Got it guys thanks, for future reference just ground the thermal cutoff wire (orange) to the ground wire in the harness and then the hot wire to the green then just plug the harness into the the connector and boom.

 

Glad you figured it out, but I'm just curious about what you mean by "waste of time." After I replaced the seal and the thermal switch in the compressor in my P38 it worked awesome. There was always enough pressure in the tank to cycle through the height settings, and the compressor didn't run very often so the duty cycle and output of the stock compressor was never an issue. Do you have leaks that the compressor needs to keep up with or are you tapping into the system to air up after a trail ride?

 

Not at all what I mean by "waste of time" is that it will always be a 15%-25% duty cycle. If you ever get an air bag leak unless you replace the air bag right away say goodbye to your pump. Plus when my OEM was working fine it still didn't lift the truck like this one does. Right after replacing the pump obviously my air system was empty. Started the truck and by the time I got out of the truck and looked it was already coming up. I would guess 45sec went by when it got to standard (From an empty tank) now I'm not one to brag, but the stock compressor could never do that.