Ignition switch fuse keeps blowing

DEANGELOSMITH

MEMBER
1999 OLDSMOBILE ALERO
3.4L
AUTOMATIC
170,000 MILES

When I turn my key to start position ignition switch fuse keeps blowing think It is labeled ign sw batt 2 under the hood. Would really appreciate some help.

Friday, December 9th, 2016 AT 2:48 PM

5 Replies

CARADIODOC

MECHANIC
33,743 POSTS

A simple trick to finding a short is to replace the blown fuse with a pair of spade terminals, then use small jumper wires to connect them to a twelve volt light bulb. A brake light bulb works well. When the circuit is live and the short is present, the bulb will be full brightness and hot so be sure it is not laying on the carpet or against a plastic door panel. Now you can unplug electrical connectors and move things around to see what makes the short go away. When it does, the bulb will get dim or go out.

The fuses on my wiring diagram are labelled differently so I'm not sure which circuit to look at. Can you find some items that are dead when this fuse is blown? What is the current rating of this fuse?

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Friday, December 9th, 2016 AT 4:36 PM

DEANGELOSMITH

MEMBER
17 POSTS

Thanks, will definitely try the light bulb test. I had not noticed anything not working since it just happened today and had to leave the car at work. My fans are wired to my fuse box and they usually turn on when the key is in start position, but not anymore since blown ignition fuse. It is a 30 amp maxi fuse.

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Friday, December 9th, 2016 AT 5:19 PM

KEN L

MASTER CERTIFIED MECHANIC
42,913 POSTS

It sounds like you have the fan motor is shorting out causing the fuse to blow. Unplug the fan motors and retry, if the fuses don't blow you should replace the fan motor. Try amazon they have them for cheap.

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Monday, December 12th, 2016 AT 1:44 PM

DEANGELOSMITH