Ammeter help request.

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Apr 17, 2007 | 02:40 PM

firstimer

Thread Starter

Racer

Joined: Oct 2005

Posts: 469

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From: West Slope of the Sierras California

Ammeter help request.

O.K., here's where I'm at....gauge has shown no movement ever since I got the car, even after I had the batt. go down. Now have the inst. cluster pulled and used a AAA battery on the terminals (found this test in a search) still no movement. Bad gauge? Tested with polarity both ways. What would be the proper test to the wires in the plug-in to insure there's correct juice there? Just to be sure the fusible link isn't fried as well. Also, should the gauge be unplugged before doing the AAA test? (Battery is disconnected.)

Thanks, Randy

Apr 17, 2007 | 03:06 PM

SIXFOOTER

Le Mans Master

Joined: Jan 2006

Posts: 9,192

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From: Boca Raton Florida

with everything hooked up normal and the key on, you should get 12v (battery voltage) to both sides of the meter. The meter actually measures voltage across a known resistance (called a shunt) in your car that happens to be a piece of wire in the harness that actually carries the current. The ampmeter actually carries a very small current.
If the AAA thing didn't work the meter is probably bad. Next step is measure across the terminals of the meter itself with an ohm meter and see what you get, If it reads open, the meter is definately bad.

Apr 17, 2007 | 03:18 PM

firstimer

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Racer

Joined: Oct 2005

Posts: 469

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From: West Slope of the Sierras California

Thanks sixfooter, I'll get to testing. IF the meter needs to come out, looks as though 4 hex head screws on the back of the cluster takes it loose from the bezel?

Apr 17, 2007 | 03:42 PM

SIXFOOTER

Le Mans Master

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From: Boca Raton Florida

Can't remember how its mounted, been to long since I took one apart

Apr 17, 2007 | 03:55 PM

7T1vette

Team Owner

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From: Crossville TN

Remove the ammeter from the cluster and take it apart enough to check the condition of the lead wires from the coil to the solder pins. Chances are that one of these wires had fatigued over the years. If you find both ends of the coil (one will probably still be connected to its solder pin), use an ohmmeter to see if the coil is open, shorted, or is still reading some low resistance (still a good coil). If the coil is still good, you just need to re-connect the bad lead wire to its pin with a little jumper wire or whatever. If the wires are both connected and you have a dead short or a full open, you will need to replace the gage.

Oh, if you are concerned about tearing up your existing gage....you were going to throw it out when you bought a new one, weren't you? Why not try to salvage it before you spend the money?

Apr 17, 2007 | 06:28 PM

gldnkngt

Instructor

Joined: Oct 2006

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From: Jupiter FL

If you don't want to drill out the rivets and take the face off to check the inner connections, and then find the rivets to rivet it back on, send it to me. These "fried" quite regularly and can be brought back to like new condition by re-winding the meter movement with the correct magnet wire. A bit time consuming, but a fairly straightforward process.

Apr 17, 2007 | 06:49 PM

firstimer

Thread Starter

Racer

Joined: Oct 2005

Posts: 469

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From: West Slope of the Sierras California

Update...

First off I want to thank all of you sincerely for all the help.
Amazing what one can do with a soldering gun (iron). My neighbor came over ( a retired aircraft welder) and after I told him about what I'd heard here, one thread I searched out telling how you can take these gauges apart and fix them, he promptly said...drill them rivets out and let's take a look. Bingo! A broken wire in the coil, a dab of solder and presto! Works like a champ! Again....Thanks a bunch.

Randy