Dash Power wire?????

Jim Lusk said

You need a wiring diagram, first. The circuit is simple, but you have to follow it. The battery has two connections on the positive post. One goes to the starter (large guage), the other to the starter relay. Another wire (red wire) goes from the starter relay to the amp guage. The other side of the amp guage (black wire) is the feed to the rest of the car AND to the large post on the alternator.

Click to expand...

Jim you nailed it, if you look at his photo it looks like the black feed wire that belongs on his stock amp gauge. Since it is no longer being supplied by the aftermarket gauge and jumper wire it is dead. If it is the stock black feed wire I think it should be connect to the stock amp gauge and see if it feeds the car. I suspect since it had an after market gauge and supply wire the stock amp gauge is dead or the stock feed (red) to the amp gauge is dead.