Dumb fuse blowing question

[BrownEyedGirl]

Winter is here with SNOW so I get my 91 Explorer licensed to drive around in 3 feet of water in and now the fuse to my rear signals and rear defrost keeps blowing. The last time I put the new fuse in, it blew when I started the engine. The "rear anti-lock" light on the dash comes on when this happens. People say "oh you have a short" but what does that mean????????? I suppose I have to go to one of those $$ mechanics?????

Thanks for any advice.

[hogfan1959]

The term "short" refers to possibly a wire shorted to ground. If you have a multi-meter or an ohm meter, set the meter to read continuity. Place 1 lead (with blown fuse removed) on the load side of the fuse holder and the other lead to a good ground on the frame. Load side refers to the side of the fuse that is not powered. To check this, set meter to volts DC, put the black lead to ground, and check the fuse holder with the red lead. With fuse removed, there should only be power on one side of the fuse holder.

If the wire is shorted, the meter will deflect full or read something to the effect of "ovl". To check what happens, touch the meter leads together.

Should you determine that you do have a short, all you can really do from there is chase the wire to look for a nick or cut somewhere. Hope this helps.

[BrownEyedGirl]

Somewhere to start!!

[hogfan1959]

Originally Posted by BrownEyedGirl

Somewhere to start!!

Sorry, I forgot to mention that if the rear lights (or any device) are involved in the circuit, it's possible that you will show a short to ground at first. If this happens, remove bulbs or unhook ground wire and try again before chasing the wire too much. The bulbs would give you a reading to ground if they are good.

[GIN]

Isolate the problem.
1)Put the vehicle in 4WD LOW - I believe this cuts out the anti-lock system, replace the fuse and try again.
2)Remove one of the leads from the rear defogger, replace the fuse and try again. I doubt if this will fix it.
3)If it still blows the fuse, remove the brake light bulbs one at a time and try again.
4)Do you have a trailer hitch wiring harness on this vehicle? Eliminate that.
5)Do your four ways work, do your turn signals work, does your cruse control work (I mention this because the brake lights are tied to the cruise control)

Hope this helps/Let me Know/Mike