My 88 XJ's AC stopped working the other day. I can hotwire the clutch at the condensor to the battery and the AC turns on. However, its not working from the dash and the fuse is not blown. Is there a relay somewhee that I can test for power to help isolate the issue? Thanks!
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88 XJ - AC fuse ok but not engaging clutch
- Thread starter SoCal88XJ
- Start date
5-90
NAXJA Forum User
- Location
- Hammerspace
You may be low on refrigerant. Check by bridging the Low Pressure Cut-Off (LPCO) switch atop the accumulator with a jumper lead. If the aircon clutch engages with the switch terminals jumpered, either you're low on refrigerant and need a recharge, or the LPCO switch has failed - with the low refrigerant charge being more likely.
The LPCO is meant to help prevent compressor burnout - if the refrigerant charge is too low, oil will not circulate properly through the system and parts will begin to fail...
- Location
- on the beach in Ocean View, VA
just to clarify-- you want to bridge/ jumper the wires in the socket that attach to the switch-- not the switch
eace:Pulled the switch and the cold idle dropped down very low for a few seconds then recovered. Jumped the wires to the switch and nothing changed. If I disconnect the main wire to the pump and touch it to the battery 12v pos, the clutch engages as it should and begins running the AC. Is there anything between the dash switch, the fuse in the fusebox and the condensor, like a reay that I could test at?
5-90
NAXJA Forum User
- Location
- Hammerspace
There is a relay - it's one of the four behind the battery, but I don't recall which. If you do a search for <RENIX Relays> and variations, you should find images that others have posted here keying those relays (I know three of them are the aircon clutch, fuel pump relay, and HEGO heater relay. I don't recall the fourth. The "odd man out" - metal case - is the starter motor relay.)
The four relays - and a couple of others scattered around the body - are standard DIN relays, and they can be had anywhere for ten bucks or so. Since you should keep a couple with your spare fuses and lamps, testing by substition becomes quite practical - just make sure you're swapping the correct relay. If I could find my 1990 FSM, I'd take a pic of that page for you (but I can't find the damned thing at the moment...)
