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2015 toyota corolla

I recently found that my side view mirror defroster fuses were missing and wondered if I can use a 20 amp fuse instead of 15 amp fuse?

NO 8, 7, 6, 5, 4, 3, 2, 1 Stupid 10 character limit

Coworker bought a older Ford Focus for his son. He was having some electrical problems. Prior to purchase someone had replaced a fuse for the rear defroster or tail lights with one with a higher amperage. The higher current through the circuit damaged the wiring harness. $2000 and a replacement wiring harness later the car passed inspection.

Replace with an equivalent fuse, if the new one blows then there is a short in the circuit.

Ed B.

Wow! Heated mirrors! The Corolla has come a long way since 2006 (my trim didn’t even come with power locks).

Any knowledge as to why the fuse was missing? I installed 12v electronics for 8.5 years, and sometimes saw a fuse would be removed when a feature stopped working. Installing a larger fuse might allow the enough current to allow these defrosters to work, or it might set your car on fire, so I don’t recommend it. You see, circuits are designed with a certain gauge of wire, that handle only certain amount of power and use an appropriate size fuse. Put in too large a fuse, if the circuit starts drawing too much current (like this one is probably doing and hence someone removed the fuse), and you start getting lots of heat, and if you haven’t lived a clean life, you get fire!

I surmise that one of the defrosters is defective and is drawing too much power, and needs to be replaced if you need it to work again, or you have a pinched and shorted wire, which is hardly the case in Toyotas. Last possibility I foresee, someone blew a circuit and needed a fuse, so they “borrowed” from an often unnecessary circuit, and never replaced it. Does anything else in the either of the front doors malfunction (ie locks, power window, speaker, or even dome light), or does anything electrical in the vehicle not work other than these defrosters?

Best of luck!

I believe the “cigarette lighter” or better called, power outlet uses a15 amp fuse, so I’m really liking my last theory of the borrowed fuse. I should stress what I alluded to, just as a prior commentator did, do not put a fuse in with a current rating that’s higher than what’s specified, otherwise you’re asking for trouble.

Are you sure you HAVE heated mirrors? The fuses might not be there because your car doesn’t have that option.

Cars are often wired to accommodate all manufacturer-offered options including dealer-installed ones, and things like the heated mirrors and the fuses left out unless the option is ordered. When I installed driving lights in my Scion I used the OEM wiring harness installed in the car for the manufacturer-offered driving light option, even though I was using aftermarket lights. I had to also buy a small trifurcated harness, a Toyota relay, and a switch, but the main harnesses were installed in the unibody.

I’m willing to bet that should you want heated mirrors you’ll have to purchase a small additional harness, different mirrors, and a relay and switch, as well as have a wiring diagram to hook it all up.


I purchased the car two years go brand new off the lot. On the sales sticker it says heated mirrors.

I purchased my Kia in May 2010 and did not know it had heated mirrors until October when the rear window had heavy condensation so I pushed the rear defrost button and was surprised when the mirrors quickly cleared.

Than look in the owners’ manual for the fuse size. It’s usually printed on the fusebox cover too, but that gives you two sources for the information. Take the fusebox cover off and look at the underside.

So I waited for a cold morning pressed the rear defoster and to my surprise the side view mirrors do warm up. So why do they have a fuse slot and label? It doesn’t matter I guess. Problem solved.Thanks everyone

Did you read your owner manual? I guess not

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Do you have an answer for why there is a fuse slot
when one is not needed? Or do you have no life and troll when your lonely.

It’s probably that they are using a fuse box design that is installed in several different versions of the Corolla, other models like the Camry, and/or that design was used in prior model years. Your version of the car doesn’t require that fuse slot have a fuse installed, but others do. The factory service manual wiring schematic would be where to look if you desire to know more.