Automotive Air Conditioning Information Forum (Archives)

1SharpGuy on Tue June 24, 2014 11:43 PM

Year: 1997
Make: Chevrolet
Model: Express Van 1500
Engine Size: 5.7L
Refrigerant Type: R-134a

I am replacing the GM OEM compressor on my 1997 Express Van with an after market compressor. The after market compressor did not come with a high pressure switch installed on the unit. What is the purpose of the high pressure switch? How does it work and effect the operation of the compressor? Is it necessary to install a high pressure switch inorder to have a properly functioning compressor? Will the compressor function w/o a high pressure switch installed?

webbch on Wed June 25, 2014 8:00 AM

The HPCO switch is a protection mechanism for the compressor - as the acronym suggests, at high pressure, it shuts off the compressor. On my '90 Chevy truck, when I replaced the compressor, it didn't come with a new HPCO either; that port was blocked off with a plug. I removed the plug and transferred the switch from the old compressor to the new.

The new compressor will run without it. I dunno, since it's already there, I'd just transfer it over to the new compressor (or buy a new one). You have to evac the system to install it though, so make up your mind before you charge the system.



Edited: Wed June 25, 2014 at 8:02 AM by webbch