Will the car run if ammeter is open ? ( plug is not plugged in on back on ammeter ) Car runs.

I am helping a friend. Ammeter did not work. Substituted another ammeter, still no work. Checked his ammeter with ohm meter -- open, --- it's bad , so we have two problems . Did not think car would run with open ammeter so I assumed ( which is a bad thing to do) someone had bypassed ammeter. I am trying to find where they made this change. I have a short from starter solonid to alternator output--- makes sense if ammeter is not in circuit if it has been jumped out. Thought , since I can not find the jumped connection, maybe car will run without ammeter plugged in, lets ask another 72 vette owner. We are not in a hurry so any answers would be appreciated. I have looked at the schematic and have found most of the points needed , horn relay etc..

 

Welcome to the forum.

Without the benefit of having a schematic, I am assuming that the ammeter is really a voltmeter measuring the voltage drop across a very low value resistor. As an example, if you were using a 0.1ohm resistor and you measured 50 volts, that would be the equivalent of 5 amps. It's the old V=IR formula or in this instance, I=V÷R.
I don't think a bad or missing ammeter would prevent the car from running. It might, depending upon how the circuit is set up, prevent the battery from charging.

 

It's nice how some people will take a few minutes of their time to help another, forums are great, my Dad had to figure it out himself.
This 1972 does have an ammeter, not sure when they switched to voltmeters. Thanks again pete !!

 

I think you might have misunderstood me. I didn't mean that his ammeter was really a voltmeter and showing voltage. What I meant was is they're using a voltmeter and measuring current through what is normally called a current viewing resistor. I really have no idea if that's what they're doing or not. But I can almost guarantee you that they're not running 30 amps of current through the meter in the dash.