Recently got a ‘96 FZJ80 and I don’t *think* the AC worked since I got it, but not sure. For sure though it hasn’t worked the last few weeks. It is manual climate, not Auto. Initial symptoms were the AC clutch was not engaging. The light on the AC button comes on and the relay behind the glovebox clicks.
Things I have done:
- checked auto/manual switch on back of climate controls (it remains on manual as expected)
- replaced the relay behind the glovebox, with a few others. (No change, still clicks on as expected)
- jumpered the plug for the in-line sensor by the battery (no change)
- unplugged the coolant temp sensor on the block next to the oil filter, no change (AC clutch still gets 0.5v)
- took out the AC computer thing behind the glovebox, and disassembled it, it looks clean and no bad resistors or corrosion (at least visually)
- discharged the system, pulled a vacuum, tried to recharge and the AC clutch still doesn’t kick on
- multimeter tested the 1-wire plug to the AC clutch. It only shows 0.5V or so
- ran a wire from the battery to the AC clutch directly, it DOES kick on and work normally, and I was able to charge the system with R134 and it’s all good… when manually controlling 12v to that wire
So, for some reason the AC clutch is only getting 0.5V through the system normally
What’s the troubleshooting step here?
Are there other relays? Do I just replace the AC computer thing next?
EDIT: well after retrying everything above AGAIN (except discharging and recharging) I was able to find the culprit: the coolant temp sensor on the block (88790-60050). Must have accidentally had something unplugged before when I had tested it. Apparently it’s remaining partially closed and giving a super weak ground so the AC clutch barely gets any power.
For now I left that unplugged, and ordered a replacement. Doesn’t seem to have any other consequences (other than it’s safety function to shut off the AC when the engine gets too hot)
Things I have done:
- checked auto/manual switch on back of climate controls (it remains on manual as expected)
- replaced the relay behind the glovebox, with a few others. (No change, still clicks on as expected)
- jumpered the plug for the in-line sensor by the battery (no change)
- unplugged the coolant temp sensor on the block next to the oil filter, no change (AC clutch still gets 0.5v)
- took out the AC computer thing behind the glovebox, and disassembled it, it looks clean and no bad resistors or corrosion (at least visually)
- discharged the system, pulled a vacuum, tried to recharge and the AC clutch still doesn’t kick on
- multimeter tested the 1-wire plug to the AC clutch. It only shows 0.5V or so
- ran a wire from the battery to the AC clutch directly, it DOES kick on and work normally, and I was able to charge the system with R134 and it’s all good… when manually controlling 12v to that wire
So, for some reason the AC clutch is only getting 0.5V through the system normally
What’s the troubleshooting step here?
Are there other relays? Do I just replace the AC computer thing next?
EDIT: well after retrying everything above AGAIN (except discharging and recharging) I was able to find the culprit: the coolant temp sensor on the block (88790-60050). Must have accidentally had something unplugged before when I had tested it. Apparently it’s remaining partially closed and giving a super weak ground so the AC clutch barely gets any power.
For now I left that unplugged, and ordered a replacement. Doesn’t seem to have any other consequences (other than it’s safety function to shut off the AC when the engine gets too hot)
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