Two questions, one post.

[maximoutlaw]

Right below the ignition switch which is mounted on the bottom of the dash I have two wires that my mechanic had hooked an amp gauge to. (I have a 68 wiring harness in a 70) After driving the car for the first time ever I started getting a lot of smoke in the cab of the car. When I got home I realized it was coming from the amp gauge and that some of the plastic pieces were melted on it. I took it off and after that the car wouldn't start.

My mechanic came over and told me that I needed a volt gauge for it and that if I connect those two cables the car will start. I bought a volt gauge and hooked those two wires up to it. When I turn the ignition, the volt gauge gets a reading but the car won't even turn over, but once I touch those two wires together again it'll start right up. It'll quit though as soon as i take them apart. I tried leaving them together and about a minute later I saw smoke coming from the cable and they were hot to the touch. I was told it might be a ground issue but I wouldn't even know where to start looking if that is even what it is.

My second question is that is there a guide to removing the gauge cluster? I tried tackling this one myself but I got frustrated after trying to pull it out at every angle possible. It seems the steering column keeps getting in the way.

[elacruze]

On a '68 the Amp gauge is the connection to all the interior circuits, and without it you have no ignition switch. A voltmeter only passes a very small amount of current, so will read the incoming voltage but won't pass it through. You can attach the wires together and bypass the amp gauge and supply electricity, and you can add a voltmeter in parallel to that connection to know the system voltage.

The first thing you need to know, though, before you do anything else is why the circuit got so hot. The alternator charges the battery through that circuit, so you have a lot of current moving through it. Likely, it's due to an undercharged battery which can be rectified by using an external charger before starting. You have to consider also that the battery may be faulty and causing the alternator to work too hard, or that the voltage regulator is stuck and the alternator is working full capacity all the time. Either way, you'll end up cooking something.

Charge the battery fully with an external charger. Get a multimeter, and test the system voltage right away after starting to be sure it doesn't go above 14.5 volts, and settles to something like 13.5 after 30 seconds or a minute.

[troutstreamnm]

Sounds pretty serious!  Was your ampmeter working properly when the wiring started to fry?

[maximoutlaw]

So basically any time I have a low battery it'll do that. Is there no way to fix that? How would I tie a volt gauge into it to see if I have the right amount of volts?

[Nacho-RT74]

firts we need to be sure did fit the RIGHT amp gauge... mostly aftermarket units are shunt kind what is kinda a remote amp gauge, so you could probably mess up the new AMP, not designed to drive the load