Replaced car battery, now A/C has weird smell

ACORN8

MEMBER
1999 TOYOTA 4RUNNER
3.4L
V6
2WD
AUTOMATIC
310,000 MILES

I had Walmart replace my car battery about 3 weeks ago, and ever since, there is a strong smell coming from the A/C even when I turn it off, but much more so when it's on either blowing hot or cold, doesn't matter.

Hard to describe the smell, but I don't think it's mold or mildew. Perhaps an "electrical" or "burning" smell?

I've replaced the battery in this vehicle many times (including same model battery top rated by Consumer Reports at this same Walmart 6 years ago) never had a problem like this!

What on earth could be going on?

Vehicle listed above SR5 model.

Any thoughts would be greatly appreciated!

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
47,643 POSTS

Hello,

It sounds like the alternator is overcharging or throwing AC voltage the battery causing the old battery it fail and the new one to smell. Here is a guide to confirm the issue that the alternator needs to be replaced and here is a guide to walk you through and the alternator replacement instructions for your car int he diagrams below:

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

and

https://www.2carpros.com/articles/how-to-replace-an-alternator

Check out the diagrams (below). Please let us know what happens.

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