Battery/charging light is on and the battery and alternator are good

JONAHPK

MEMBER
2004 TOYOTA HIGHLANDER
11,100 MILES

2004 Highlander Limited w/3.3L V6-110,000 miles

AC clutch and cooling fan come on when car is off. One morning last week I came out to find the cooling fan running on the car. I unplugged the fan and went to work. Two days later the battery was dead. I charged the battery and the charging light came on the dash. The car runs fine, unless I turn on the heater or AC. I checked the battery and alternator and they are both fine. After checking fuses and other connections I went to put the ground terminal back on and noticed that the AC clutch engaged.

I unplugged the AC compressor and the cooling fan comes on and the battery light stays on. I unplugged the cooling fan relay and the light went off. But, the car won't run for long at idle this way. If the car dies, I hear some inconsistent clicks from the fuel pump and some clicks under the dash to the right of the steering wheel. I am just about at my wits end chasing this issue. Help?

3 Replies

MHPAUTOS

MECHANIC
31,937 POSTS

I have seen this problem before the ECM is out and needs to be replaced because it control both the alternator and AC. Here is the location and I would try a used one you can get from Ebay.

Check out the diagrams (Below). Please let us know what you find.

Cheers

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