67 Mustang ammeter problem

[47convert]

My friend has an original '67 Mustang he bought brand new and it's pristine BUT, the other day there was smoke coming from the ammeter. The Ford book says this is an ammeter, not a voltmeter with an ammeter label like some cars, but it has pretty small wire -- like maybe #14 at the most. He's got a new ammeter but when he connects it it goes to full discharge with any kind of load at all. Even one tiny light bulb sends the meter full scale. I'm thinking there must be a shunt around the meter that handles most of the load normally and that it may be open. Any ideas?

[wayne petty]

don't connect the battery yet...

there are 67 mustang wiring diagrams all over the place online..

there is an OPEN.. causing all the amperage to try to pass through the amp meter....


i have to run out..  will be back in a hour or do...

first place to check is the various grounds...    between the battery negative.. the hold down  clamp that is part way down the cable and attached to the inner fender.  this clamp if you notice is NOT on top of the insulation  its crimped right to the conductor.. so it it how the body gets its ground connection..    there should also be at least one ground wire from the engine to the firewall also...

[wayne petty]

the mitchell wiring diagram i have for the 67 mustang.. shows a violet wire from the back of the amp meter that ends up possibly as a black and yellow wire that tees off to power other items..


the other wire is yellow from the back of the amp meter.. this hooks to the battery side of the starter relay ....


if you have lost connection at either end.. via a dirty connector.. a burned fusible link... a bad fuse...  corroded connector...

what's happening is the normal circuit path is open.. so all the current is trying to flow through the amp meter...

what i would do is disconnect the amp meter.. then look for circuits that now don't have power....   figure out where they normally get the power from and fix it..


if you need a diagram.. drop me an PM... with your email.. mention 1569.

[wayne petty]

why is this happening...

the amp meter usually does NOT have much current flowing through the circuit.. it just looks at the difference in the load between the 2 different connections...

why it burned... some circuit opened.. sending ALL the current flow through the amp meter...

[47convert]

Well Wayne, Once again You nailed it. My friend says he found a bad connection at the starter solenoid. Many thanx! Boy, I just looked at my "User age and realized I've been around here for a lot of years!