Automotive Air Conditioning Information Forum (Archives)

e6ug on Tue August 13, 2013 7:11 PM

Year: 1988
Make: jeep
Model: cherokee
Engine Size: 4.0
Refrigerant Type: 134a

i was able to replace the bad heater core without unhooking the ac lines, was a PITA, but i got it installed and everything put back in place But now my ac clutch wont engage. i tried jumping the low pressure switch and nothing happened. i have replaced the ac clutch relay, i am not sure what else to check.

i had the system professionally converted to 134a about 3 month ago and it had been working great all the way up to the heater core job.

is there anything behind the dash or under the hood i might have accidentally disconnected during the heater core job that would keep the compressor clutch from engaging? when the shop charged my system they added a green dye for leak detection. when i did the heater core job i did not see,smell, or hear any leaks.

e6ug on Tue August 13, 2013 7:32 PM

figured it out. somehow i forgot to reconnect the condenser temp switch attached to the HVAC box, above the pass foot area. kinda behind the catch tray below the glove box.

GM Tech on Tue August 13, 2013 9:55 PM

evap temp sensor

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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......