A/C Issues

[MA70-3.0GT]

I'm wondering, if you replace the fuse as soon as it blows & switch back on straight away does the fuse blow again straight away or does it take another 10mins to blow?

I ask this because if the fuse takes another 10min then the clutch windings or a bad connection could be drawing too much current causing the fuse to heat up & eventually blow, but if it blows straight away then more likely there's something being affected by heat/cold and shorting out.

If you suspect high current draw not dead short then you can measure it using a multimeter with it's probes in place of a fuse, and maybe also compare resistance readings between the clutch windings on your car & one that's known good. Also you could perhaps go through the connections & grounds for the AC clutch anyway and just make sure they're all clean & wiring isn't chafed/corroded.

If you suspect a dead short then you could also use the multimeter (but don't try to measure amps!), this time by using the AC until it blows the fuse & then checking resistance in the clutch windings & through other areas of wiring, and also check for shorts to ground in the supply wiring.

I suppose the clutch windings could be at fault but I have to say I've never experienced it on any vehicle before, I'd have to say it's more likely a wiring/connection problem & therefore easier/cheaper to fix. But a session with the multimeter will tell you more anyway. HTH

EDIT-: Here's the TSRM section on testing the clutch windings, there's the specs for the winding resistance values http://www.cygnusx1.net/Supra/Librar...ection=AC&P=22

Also on the next few pages are details on removing/installing compressor and dismantling the clutch. Perhaps (and I don't know how much it'd cost) you could take the windings to an electric motor specialist if they're bad & get it rewound for cheaper than buying a clutch? Or if you're like me (broke & just like fixing stuff for the love of it) you could even look into rewinding it yourself...
Best of luck

Another EDIT-: Here's the part of the TEWD http://www.cygnusx1.net/Supra/Librar....aspx?S=D&P=30 showing the wire from the 10a A/C fuse. It's the v/r (violet?/red) wire at the top, it runs from the fuse to a plug where it goes to the pressure switch and the A/C amplifier, from there it becomes a y/g (yellow/green) from the pressure switch & a l/w (blue/white) from the amplifier, which plug together & send a y/g (yellow/green to the relay & then an l (blue) from relay to clutch. If the clutch Ohms out OK then these are the connections/wires to check next...