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View Full Version : Trouble with a blowing fuse : dead short



Tony_SS
02-24-2012, 06:30 AM
This one has really got me. I have a dead short somewhere, and for the life of me cant find it. It's on the courtesy fuse, which has a few items on the circuit: power locks, horn, cig lighter, radio, int lights, trunk light. Every time I put a fuse in there, it pops. So I unhooked the radio and cig lighter, it still does it. I've cut the trunk light, still does it... double checked all the wires I could find and nothing shows....

I've jumped a headlight up to fuse using this method (http://www.crookedriverwriter.com/index.php?/Automotive-Topics/the-old-headlight-trick.html) and it lights it all the way up and moved around a bunch of wires near the fuse box and it just stays lit. So I have no idea where this dead short is occuring.

Any idea's on how I can trace this one down?

kmdracer
02-24-2012, 01:33 PM
I'd never thought of the headlight method, but, here's what you are going to have to do: Use the headlight method, and trace out the wire from the backside of your fuse box. You'll have to trace the circuit out in order to find out precisely where it goes. You've stated that it is the "courtesy circuit" and some/all of the loads. I'm assuming you have a wiring schematic for your car? If so, and you isolate (remove) all the loads, and the headlight is still on, you have a short in the wiring itself, and will have to physically inspect every inch of it until you find the bad spot. Sorry I don't have a magic fix for ya!

greaser
02-24-2012, 09:00 PM
Put a new fuse in while in total darkness,, You may catch where the spark is..

MrQuick
02-24-2012, 10:52 PM
Have you installed something or r&r ed anything since the fuse blowing?

Try to start the isolation at the headlamp switch. the reostat maybe shorted. Disco your battery, pull your fuse, hook up an ohm meter between ground and the fuse holder to the load side. Should be close to 0 ohms. Start pulling wires and un plugging connectors. Look for a change even slight.