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Ask Ted Ritter Your Own Question
Ted Ritter
Ted Ritter, Toyota Master Tech
Category: Toyota
Satisfied Customers: 4282
Experience:  Toyota Master Tech, ASE Certified
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My AC unit fuse keeps blowing everytime i start my car. It

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My AC unit fuse keeps blowing every time i start my car. It does not blow with the key in the ignition, the car powered on, and the AC running. Once I start the car, the AC runs for a few seconds then blows. Any ideas?
When the fuse blows does the fan inside stop running? Is the fuse that blows under the hood or inside the cab?
Customer: replied 6 years ago.
The fan still runs. And the fuse is under the hood (10A). I do not believe there is an AC fuse in the cab.
thank you, XXXXX XXXXX more question please, does the a/c compressor stop running when the fuse blows? I'm thinking that it's the compressor or the clutch that's causing this. Check the compressor, check to see if the clutch looks burned, with the engine and the key off see if the compressor center hub can be rotated by hand, there will be some resistance but you should be able to turn it, let me know if this is ok and we'll go to the next step.
Customer: replied 6 years ago.
Ok. The compressor does not stop turning with a blown fuse. Also, I was able to turn it. I do not know how to find the clutch so I cant tell you if it looks burned. How do you go about doing this? And im assuming I would need to take off the skidplate.
No, you can see it from the top it's on the front of the compressor, the outer pulley is turned by the belt, the smaller pulley in the center is the pulley that engages and turns the compressor, I hope this is the one you turned by hand. It's kind of recessed in the larger pulley so just because the outer pulley is turning it doesn't mean the compressor is turning, I need to be sure that the center pulley can be turned or doesn't stop when the fuse blows, you may need a flashlight to see the center pulley.

Edited by ted ritter on 5/17/2010 at 10:34 PM EST
Customer: replied 6 years ago.
Yes, that is what i turned. It protrudes out from the belt correct? I also watched it as the engine was cranked. Like I said earlier, the AC fuse doesnt blow when the key is in the ingnition and power to the truck is turned on. When the engine was cranked, the clutch spun one time and the fuse was blown. After the fuse was blown, it stopped turning. Is this what you needed?
Excellent, thank you very much, this confirms my suspicon that the compressor may be the probable cause or the clutch is shorting out, these are the only two things that will make that fuse blow, think about it this way: with the key on and the a/c not running the fuse doesn't blow meaning that it's not a short circuit in the wiring, only when the clutch engages is current drawn through the fuse to keep the clutch engaged and the compressor running, if the clutch draws too much current the fuse blows, this can also happen if he compressor seizes up causing too much current to go through the fuse. The solution? I think it's more likely to be the clutch than the compressor itself going by past experience, so I would replace the clutch first, since it takes some special equipment, like an a/c service machine to get the freon out, because the compressor has to be removed, some tools to remove the clutch etc., I would not recommend this as a do it yourself job unless you feel you can do so, you may be able to do it without removing the compressor, let me know if more help is needed with this.
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