66 Valiant Electrical Issue?

A great big short is why the link popped. Those things are not much protection. Lots of harnesses have "welded themselves" into a mass of smoking plastic before the link finally popped


Before you do much, Get a lamp in series with the battery ground. This will limit current if you DO get the short to reappear, so that you don't burn something up.

A good setup for this purpose is a "nice big" lamp. An old headlight, or a stop / tail light socket works good. Just wire it from in series with the battery ground. A quick way to connect to a tail lamp socket is to take a small worm drive hose clamp and just clamp a wire to the socket.

YOU MUST have the two ammeter leads hooked together OR the ammeter hooked up to get power to everything. It IS possible I guess for the ammeter to short to ground, I'm not very familiar with the older clusters.

Look up at the simplified diagram I posted from the MAD article. That IS most of the stuff that will pop the link. Only thing not shown is a couple of things not shown that branch off from the "welded splice."

To inspect the splice, you start at the black ammeter wire, and tie off the harness as you go, untape it down a few inches, following that black. The splice is down in the harness a few inches, I believe less than a foot.

The "in harness" splice feeds:

1 The hot buss in the fuse panel. You should be able to pull fuses and eliminate any shorts there

2 The main feed for the IGN switch. Note that except for the fuse link, this is NOT fused

3 On many models, the wiper switch, which has it's own breaker

4 Headlight (not tail or park) power to the headlight switch, which has it's own breaker

5 Might be one other path, not sure.

LAST NOTICE that from the battery, through the harness, the END of things is the ALTERNATOR. An alternator can generate an impressive short as Steve, 4spdragtop can tell ya. If just one diode in the alternator shorts, or some other internal problems, it will cause a "dead short" which will do this very thing, so the FIRST thing I'd do after hooking up your lamp, and hooking the ammeter wires together, is to remove the wire from the alternator and tape it