C3 ammeter

[William S.]

The ammeter in my 69 has gone bad. I've tested the charging system and verified that the correct voltage is getting to both posts even though it reads -40. I bought a new ammeter several months ago and am just getting around to putting it in. I decided to test it first by touching the leads to an AA battery and can't get the needle to move off zero. I also tried clamping each of the leads to the positive battery terminal with the same results.

Did I get a defective ammeter or am I testing it incorrectly. I don't want to tear the dash out without a good one ready to go in.
Thanks.

[Dan M.]

Re: C3 ammeter

WILLIAM

Think you are confusing current (amps) and volts. The ammeter will measure the amperage going to the battery but to put a small battery across the ammeter will not draw any amps and hence will not move the needle on your new guage.

An Ammeter needs to go in line with the current your alternator puts out to read properly. The quick battery test you did does not do that so your new guage may in fact be fine.

[John H.]

Re: C3 ammeter

WILLIAM

Think you are confusing current (amps) and volts. The ammeter will measure the amperage going to the battery but to put a small battery across the ammeter will not draw any amps and hence will not move the needle on your new guage.

An Ammeter needs to go in line with the current your alternator puts out to read properly. The quick battery test you did does not do that so your new guage may in fact be fine.

NOOOOO! It's NOT an "ammeter" - their last usage was in 1962. From '63-up, the "Battery Gauge" is a sensitive voltmeter (galvanometer) whose two leads sense voltage at two points - the big battery cable stud on the starter solenoid, and the hot buss on the horn relay, and the needle displays the voltage difference between those two points (using the wiring between them as a shunt) to indicate current flow in the charging system TO or FROM the battery.

If a brief touch of the two terminals with a AA battery doesn't result in needle movement, the gauge is bad.

[Richard R.]

Re: C3 ammeter

William, use the search option at the top of the page.type in c3 ammeters. there is some good info available. hope this helps