A/C fuse keeps blowing

1999 Toyota Corolla
Went for a long trip and at my destination,the a/c 7.5amp fuse blew.Replaced with a 15amp fuse but it blew right away.Next day,when engine was cool,I took a spare 15amp fuse and a/c started working as it should.I drove the car all day without any problem.Is there something else I should watch for that caused that fuse to blow in the first place.

If the original fuse was 7.5 best to replace it with the same. Putting a higher rated fuse will keep the fuse from blowing but some other component not rated for a higher load could fry. If you are old enough to remember folks would replace a screw in fuse with a penny, terrible idea and the cause of a few fires. As for the A/C trouble, I will defer to more knowledgeable folks.


This problem will go away… in a fire… if you don’t remove that 15 amp fuse and replace it with a 7.5 amp. If you are tired of the 7.5 blowing, take it to a good AC shop and let them find the electrical problem causing the fuse to blow.


The fuse is rated primarily to protect the wiring from burning up in the event of a load fault. Sometimes there is a lot of margin in the design and components, sometimes not so much…

Here’s another vote to put in the proper fuse before the wiring catches on fire.


Without a wiring diagram in front of me, my first supect would be a dragging blower motor. An amp test of the blower should easily show this.

As mentioned, you had best remove that 15 amp fuse because if you don’t eventually some wiring is going to fry and/or a fire is going to flare up.

Back in the late 80s an older Subaru was towed in for a no-start. Apparently the 7.5 amp headlight fuse kept blowing. This was the days of glass fuses. So he adds a 10 amp whch blew. This was followed up by 15s. 20s, 25s, 30s, and so on. Eventually there was a huge cloud of smoke and the tow truck was called.

What did the guy do when he couldn’t find a fuse with a high enough amp rating? He removed the combination Phillips/Common blade from a utility screwdriver and inserted that into where the fuse was supposed to be., That cured the fuse problem at the expense of the entire front wiring harness.

Ok,I replaced it with the proper fuse and everything is working fine.I picked up the fuse at my Toyota dealer, it was costly but worth every penny.That 15 amp fuse that blew the second time was a really cheap 10 cent fuse.