Car Electrical Issue - Fuse Sizes

One of the fuses in our minivan went bad on us about a month ago - controlled the dome light, electric mirrors and various other stuff.

It was a 10 amp fuse. I replaced it, and all was fine.

The same fuse just burned out again. Bringing up a couple issues:

  1. Does this mean I need to get the car checked out at the shop? (Same fuse twice in a month or so)?

  2. I don’t have an extra 10 amp fuse around - trip to the part shop is 30 minutes round trip. Can I use a 12.5 or 15 amp fuse? Is this unsafe or bad for any particular reason?

Try a .22 caliber bullet.

I was sure that someone who knows something about the subject would reply after I wrote the stupidity that I did previously.

My serious answer would be that it isn’t a good idea to replace a fuse with a higher rated one. If the fuse doesn’t blow, something else might burn out. It seems that you might have a short somewhere. The best bet is to purchase a new 10 amp fuse and take the vehicle to a professional.

Worst case scenario is that you put in a higher rated fuse and set fire to your wiring harness. This will cost a crapload of money to replace.

This is anecdotal from stories heard from friends. I might be totally wrong.

Good luck.

Yeah, that’s what I was afraid of. Trip to parts store now, plus probably repair later…


How much does a 10 amp fuse cost? Why not buy 20?

There’s got to be a reason why you’re burning out the same fuse.

Troubleshooting thoughts:

Has it rained anytime recently were you are? - Leak somewhere causes Short Circuit
Have you added anything to the vehicle? - Bad Wiring, exposed wire, torn insulation
Does it have any after market items installed? - Same as above
(Phone hands free kit, Video Player, Radar detector, etc.)

Nothing changed on car in last year+. I don’t think it’s rain either. Probably just something wore down/out. I replaced the fuse. If it goes out again, I’ll take it to a shop.

Roger’s Mechanic friend says:

Sounds like you have a short or high amperage draw in the system. If it’s the same circuit as dome and interior lights, those little bulbs are notorious for going bad, but not actually popping the filament like a normal bulb. As such, they tend to draw at a higher load, but since they are usually not on for long enough to finally give out, the fuse suffers first.

You have several options:
1.) If you don’t like to mess with things like that, take it to a mechanic. Preferrably a mechanic that enjoys electrical puzzles.

2.) If you do enjoy electrical puzzles, you could use a multimeter and see what the draw is across the circuit at the fuse box with the circuit hot. It’s best to have a wiring diagram to make sure you know what all is on that circuit so you catch everything. If it’s really high (like over 20amps), then you can start removing the interior bulbs and moving the mirrors around to see which one causes the load to change a bunch. If it’s only like 12amps (slightly above the stock fuse load), you can just put a 15amp fuse in it’s place, and not worry about it. The difference is not enough to cause worry.

Considering the power mirrors are involved, if you have kids that sometimes play with that, you may have found your culprit. If those mirrors are moved to their limits, the motors go under high load, and their power consumption spikes (this is how most “auto down” window switches work; they wait for the power window motor to spike when the glass hits bottom, and then cut off). As the motors age, the normal power consumption and load spike gets even greater. It maybe just enough to pop the fuse.