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1991 Nissan 300zx
My AC stopped blowing cold air about 5 weeks ago, the R12 is a little on the low end but not low enough for the low pressure sensor to stop it. To be sure I skipped the low pressure sensor and connected the compressor to the battery and it began blowing cold air. I notidced the Air Con fuse was blown so I replaced it and when the car turned on I could hear the compressor turn on. Though it was only for a second and the fuse was blown once again. I believe it may be a wire at some point between the battery and the fuse box that is shorting out. Any other ideas or information to narrow down where that bad wire may be?
Thank you very much for any information!
 

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09 Altima 3.5SE 6MT Sedan
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7,040 Posts
Inspect the clutch coil wire...it does pass by some hot parts and can rub on nearby brackets, but your description of working and then poof, it's more likely your clutch coil is dying. If it starts to short out internally, then it will draw more current than it is supposed to thus blowing your fuse. Let's say there are normally 200 windings of wire in coil and let's say each winding is 0.01 ohm (this is just an example). So your coil would normally have a resistance of 2 ohms (200 x 0.01), which at 12V would consume 12/2 or 6 amps (V=IR). Now let's say that the insulation (varnish) between winding 50 and winding 150 breaks down (could be made worse by heat) and now you have a direct short across 100 of your 200 windings...now your resistance drops to 1 ohms and your current increases to 12 amps (12/1)...
 
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