Electrical (fuse) question for you auto mechanics

[gcbryan]

I have a Toyota Corolla and suddenly the clock and radio and dome lights don't work. I checked the manual and located the buss fuse that controls this. It turns out that it is in the engine compartment.

I pulled that fuse and it is shorted out. I replaced it but as I was replacing it I could see an arc of electricity. I would have assumed that it would not be "hot" but since it's in the engine compartment maybe that's normal?

This didn't fix the problem but I'm guessing the arc I saw just fried the new fuse.
It was cold and raining outside so I didn't pull the new fuse (yet) to verify that it is fried. So assuming it is...what's likely to be going on?

What's my next step? Everything else works correctly in the car so I can still use it. I just can't see the clock, use the radio and I don't have interior lights.

Any help would be appreciated. I know very little about these things.

 

[Jim Lapenta]

It sounds like you have a short in the wiring somewhere. That fuse is getting overloaded and blowing. Time to find a garage to trace the wiring or run a diagnostic. Some auto parts stores can plug into your car and give you an idea of the issue.

 

[mrfixitchapman]

Might help if we knew which year Corolla. IIRC that circuit has the cigarette lighter as well as the radio/clock memory and the dome lights. We sometimes find that the cigar lighter has something stuck in it. Broken cell phone chargers are frequent offenders.

DC

 

[Peter_C]

What year, and which Corolla?

Unplug everything in the power ports. Turn off all the interior lights, and check the glove box light etc. Replace fuse again and see what happens. Do not put a bigger fuse in. There is a direct short to ground and it could be any number of places. Sometimes it is the wiring in the door (Typically drivers door) so you can wiggle the wiring there and see if it changes.

 

[Mopar]

I am a Electrician and I agree with all the above. Like PeterC wrote Do not use a bigger fuse. Your wire is rated for that size fuse if you use a bigger fuse it could result in a fire. If nothing is broke off in the lighter or power port get it to someone qualified. A mechanic will be able to find the short quickly. I almost forgot have you had any thing added to that circuit like a new radio or cd player? If so it could be the new device. But yes it is a dead short to ground.

 

[gcbryan]

Might help if we knew which year Corolla. IIRC that circuit has the cigarette lighter as well as the radio/clock memory and the dome lights. We sometimes find that the cigar lighter has something stuck in it. Broken cell phone chargers are frequent offenders.

DC

1994 but I don't use the lighter.

Thanks guys. Sounds like I need to take it to a mechanic and no I haven't put in a larger fuse.

 

[mrfixitchapman]

After gazing into the wiring diagrams I can see that the cigar lighter is on a separate fuse. The Dome fuse feeds the interior lights, the clock and the radio. That's all. Short to ground is on one of those circuits.

DC

 

[Peter_C]

Is there a light on the door? If so check the wiring where it bends at the door. It will be covered in a rubber tubing deal.

If no light on the door, then start disconnecting things until the short to ground goes away. Trying is free...taking it to a tech is expensive.

 

[Pudsky]

Make sure that there is no power running through that circut when you replace the fuse. Sounds like power was running through the circut when you tried to put the new fuse back in. Shut all the doors, make sure dome light switches are off. Or even disconnect the negative cable from the battery. This usually is not necessary, but will guarentee power is off. Then put the new fuse in and see what happens.

 

[gcbryan]

Thanks all. I've got it fixed at least for now. I pulled the dome cover off and saw that the fuse like bulb was not seated properly and may have been shorting things out just because of that (if that's possible). I took the light bulb out, turned the dome off, shut the doors and put another fuse in and there was no arc this time. I turned the car on and the clock and radio now work.

It was cold outside so I have tried putting the light bulb back in properly to see if it shorts again or if all is well.

Thanks again for all of the input.