Keep blowing "Room" fuse

JEHOSAPHET

MEMBER
1995 ISUZU RODEO
3.2L
V6
4WD
AUTOMATIC
169,000 MILES

The #3 fuse, labelled "Room L" in the fuse box under the left side of the dash? The 10 watt fuse keeps blowing. I bough a 15 for it yesterday and while it lasted a little longer, it ended up blowing too.
It is the fuse for my radio, interior lights and for the dinging sound you hear when you have left your keys in the ignition.

I checked the grounding on the stereo and the one coming off the battery, both look fine, but that is all I know how to do, I am at an impasse here. Anyone else have this experience or know what else I could check?

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3 Replies

CARADIODOC

MECHANIC
33,858 POSTS

The most frustrating way to find a short is to keep sticking in fuses and watching them blow, so I have a better method if you want to try it. Remove that blown fuse, then push in a pair of spade terminals instead. Use a pair of small jumper wires to connect each terminal to one terminal on a small 12 volt light bulb. For this procedure, a very common # 3157 brake light bulb works best. It has four exposed terminals that are easy to connect jumper wires to. Connect the wires to one terminal on each end of that plastic base.

When the short is present and you find the right pair of terminals on the bulb, it will light up full brightness and be hot, so be careful where you lay it or hang it. The bulb's resistance will limit current to a safe one amp, and its brightness will tell you when you do something that removes or changes the short. When you do, the bulb will get dim or go out.

If you have interior lights on the door panels, broken or frayed wires between the door hinges is the best suspect. You may see the test bulb get dim or flicker when you open or close one of the doors. Check for a glove box that is stuffed full of treasures that are pressing on the light socket.