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L98camino · 08-14-2022, 02:42 PM

1989 K3500 7.4L Silverado.
I replaced the compressor, clutch, orifice tube, dryer/accumulator and all o rings on my truck in preparation for a switch to R134. Took it to my local a/c shop for draw down and charge. After draw down he said that there is no voltage to the clutch. I jumpered the accumulator cycling switch wires and the clutch engaged. The switch showed open so I replaced it. No joy. He is adamant that I should have a high pressure switch on the compressor but the old one and new one dont have it. Nor can I find a plug that would connect to one. I have seen wiring diagrams the show 1 accumulator cycling switch and others that show the cycling switch and an a/c air inlet valve motor pressure switch. Im horse trading with him or Id try a second opinion, which is why I am here lol

Any help would be appreciated,
Thanks, Dan

08-14-2022, 02:42 PM	#1
L98camino Registered User Join Date: Mar 2013 Location: Cle Elum, Washington Posts: 10	Help! A/C techs! 1989 K3500 7.4L Silverado. I replaced the compressor, clutch, orifice tube, dryer/accumulator and all o rings on my truck in preparation for a switch to R134. Took it to my local a/c shop for draw down and charge. After draw down he said that there is no voltage to the clutch. I jumpered the accumulator cycling switch wires and the clutch engaged. The switch showed open so I replaced it. No joy. He is adamant that I should have a high pressure switch on the compressor but the old one and new one dont have it. Nor can I find a plug that would connect to one. I have seen wiring diagrams the show 1 accumulator cycling switch and others that show the cycling switch and an a/c air inlet valve motor pressure switch. Im horse trading with him or Id try a second opinion, which is why I am here lol Any help would be appreciated, Thanks, Dan