A/C keeps blowing fuses

Tiny
BANGAS
  • MEMBER
  • 1998 TOYOTA SIENNA
  • 3.0L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 177,000 MILES
When I turn on the A/C it blows the fuse for the fan. The odd thing is that It started last summer. I had a mechanic look at it in late fall, and he couldn't get the fuse to blow. He added some Freon and the A/C seemed fine. All winter and spring it worked just fine. The A/C was cold, and no blown fuses. The first day it got up to 80 outside the fuse blew again. So for 6 months in cold weather no problems. I ran it once for a couple of hours just to test it. The weather heats up and the problem is back. Any ideas or suggestion would be appreciated.
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Sunday, May 3rd, 2020 AT 9:07 AM

3 Replies

Tiny
ASEMASTER6371
  • EXPERT
Good afternoon,

I attached a wiring diagram. Can you tell me which fuse fails? There are 3 and I want to be sure I give you the correct information on the fuse.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

https://www.2carpros.com/articles/how-to-check-wiring

Roy
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Sunday, May 3rd, 2020 AT 10:50 AM
Tiny
BANGAS
  • MEMBER
The fuse that blows is the 10A heater fuse. It is located under the dash to the left of the steering wheel. So I replaced the fuse today, and now I have a fan. If I turn on the AC it will eventually blow. The first time it went out last summer and I replaced the fuse it lasted about a month. After that it would blow much faster, and sometimes almost the instant I would turn on the AC. Like I said, it has been fine all winter, and my mechanic couldn't repeat the problem. Let me know what you think, Thanks.
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Sunday, May 3rd, 2020 AT 6:23 PM
Tiny
ASEMASTER6371
  • EXPERT
Okay, I attached a picture of the fuse and circled the components that it controls.

This fuse handles power to many components and any one of them could be the issue.

The correct way of checking is to disconnect one at a time all the components and see if the fuse still fails. With all the components disconnected and the fuse fails, it will be a wiring harness issue. Wires somewhere are shorting causing the failure. If the fuse does not fail, then plug in each component 1 at a time until the fuse fails. Then you will know what component has failed.

This is time consuming to trace this down.

I also attached the ac amplifier on the lower kick panel as a start. This component is directly effected by temperature and could be the culprit but needs to be verified.

Roy
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Monday, May 4th, 2020 AT 2:24 AM

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