humblej

Compressor clutch will not engage. Atttached a jumper wire from battery to compresor connector and another to ground and clutch engaged. I know there is some pressure in the A/C system as it made a hisssing noise when I touched the low pressure schrader valve with a screwdriver. If the system pressure is low will it cut out the compressor? Will adding R12 correct the problem?

Roger Mabry

Hard to find R12 now...but a charge will allow the compressor to engage the
clutch.

Should take to shop for leak check first, O-rings go bad and you will be just
wasting time and money (freon) without confirming/fixing any bad hoses,
O-rings or other problems.

humblej

Thanks you answered my question. I have had the truck about a year, original owner died a couple of years ago (probably from heat exhaustion), so don't know how long the a/c has been out. My thinking is if there is a leak there would be no pressure by now. Original owner did almost no maintenance, a/c may have never been recharged since new, but don't know. I have a can of R12 and am thinking I will give it a try, see what happens. If it leaks out I have that answer, but suspect an a/c shop will want to convert it to R134 and that will cost some $.

GhostriderI

Also could be a bad pressure switch in the system not completing the circuit to the clutch. Just a thought