#5 fuse continually popping...

[Divine Knight]

Hello, all. Returning old timer to the forum. :) #1366 (May '81) is having a major electrical issue. The #5 fuse, which is marked as "Dash Services" on the fuse box (and actually drives a lot more than that), perpetually pops. I believe there to be a short somewhere in the system, but I lack the knowledge to troubleshoot electrical shorts. Each fuse only lasts about 15 seconds before it goes. When it pops, the instrument panel stops responding and the alternator ceases charging, going to battery-only. Also, when said #5 fuse pops, I can hear the sound of an electrical short coming from either behind the instrument panel or behind the ignition. I had removed the dash cluster about six months ago when I was diagnosing another charging problem (turned out to be the alternator, but the battery light never engaged, so I assumed that to be my problem). I *believe* I put everything back together properly, as the car ran trouble-free for about six months after this. I've crawled underneath and taken a look, although I've not removed the dash again. I didn't see anything overly obvious, but again, I'm not certain where to look. Are there any common trouble spots when reattaching the binnacle?

The ignition also has half a key stuck in it... I leave the ignition halfway engaged (enough to keep the tumblers thrown, not enough to actually engage the vehicle). If you return the ignition to the off position, it takes a good half hour to get the tumblers to re-throw. :/

[Michael]

Your fuse popping is most likely a dead short, I always tell people to look for a penny stuck in the cig. lighter. Look for all the easy fixes(pinched wires, broken insulation, foreign metal bridging contact points, etc.) before you start tracing faults with a multi-meter.

Your ignition lock is much easier, if you remove the plastic ignition lock cover, there is a small pin in the side of the tumbler casing(on the underside at approx 5 o'clock). It has backed out(or fallen out). If the pin is still there, remove it and align the holes in the lock and the tumbler case and lightly tap it back in place with a punch and small hammer. If it's gone, you will need to make one out of hardened steel(or find one at a hardware or auto parts store).

[Farrar]

Remove the fuse and put a bulb in instead. Go through every connection in the circuit and disconnect stuff on that circuit one thing at a time. When the bulb turns off, you've found which item contains the short.

[DMC5180]

That's an interesting way to find a short. Where do find a bulb that plugs into the fuse socket? Are you suggesting using a T-4 Base or similar type that has Exposed wire contacts then unfolding the wire to stick into the socket contacts.

[Farrar]

I keep a spare 12v bulb/socket with male spade terminals on short leads handy for such a purpose. If that description isn't enough, I will see if I can snap a picture for you when I get home.

[Spittybug]

I've got a little guy like this that works great when you want to keep tabs on just how much is going through the fusebox. Harbor Freight. 20 or 30 amp versions, $15 and cheaper on sale now.

http://www.harborfreight.com/media/catalog/product/cache/1/small_image/160x/9df78eab33525d08d6e5fb8d27136e95/i/m/image_14147.jpg