Ammeter pegged to the negative side, what's wrong?

[Michael B.]

Gauges recently rebuilt on my '63, but somewhere along the way the ammeter has gone completely to the left (sitting on the peg, well beyond -40). It doesn't matter whether there is power to it or not, its all the way to the left. I looked back at pictures when I installed the dash panel after it was rebuilt and it was sitting at 0.

I checked the resistance across the two terminals and it measured 0.5 ohms.

Any idea what could be wrong?

Thanks,
Mike

[Michael G.]

Re: Ammeter pegged to the negative side, what's wrong?

Mike, did you replace the wiring harness when you were restoring your car?

[Michael B.]

Re: Ammeter pegged to the negative side, what's wrong?

Yep, Lectric Limited complete replacement.

[Domenic T.]

Re: Ammeter pegged to the negative side, what's wrong?

I would think it is the needle placement. I rewound my amp guage twice and was very careful where I set the needle.

Dom

[Jim T.]

Re: Ammeter pegged to the negative side, what's wrong?

Stupid mistake on my 1968 not disconnecting the cars battery negative ground before removing electrical wires connected to battery/ammeter gauge to clean the posts. The gauges needle moved all the way to left and remained there.

Domenic what is involved to rewound an amp gauge? Is this what is involved to repair a gauge like the 68's I destroyed?

[Domenic T.]

Re: Ammeter pegged to the negative side, what's wrong?

Jim,
If your asking about rewinding the amp gauge, I did it twice on my 67. Finding the wire wasn't that hard to find when I did it the first time but couldn't font a electronics store that had it the second time. My son solved that by digging thru some common small solenoids from old parts we had and I unwound and used that wire ( only need about 3 feet). Actually I think the wire I used was off a lawn sprinkler system solenoid. You have to measure the wire for size. I am not in the shop to measure at the moment. The needle pulls off with your finger tips. On a piece of paper, draw the piece the wire is wound on. Then count the wire turns and direction. Also note the crossover to the next winding you count. I think there were four. If you miss a turn it will only affect the distance the needle moves. The first time I did it the needle moved the wrong direction showing a discharge when it was charging. That is a easy fix. You only have to switch the wires you connect to the gauge.
If it is burned you can easily see it. If not then just pop the needle and center it. A light tap with the back of a screw driver will set the needle back on the shaft. I do have the wire and if you decide to take the task on will send you what you need.

Dom

[Michael B.]

Re: Ammeter pegged to the negative side, what's wrong?

I removed the gauge and it now appears to have sprung back to +20.

I was wondering if the radio capacitor wire could have potentially shorted against one of the posts on the gauge? Which one of the terminals should that capacitor wire be attached to (if any)?

Is there any way to test the gauge or the harness in the vehicle to verify functionality of either? If I replace/repair the gauge I don't want the same problem to occur.

Thanks

[Joe R.]

Re: Ammeter pegged to the negative side, what's wrong?

Hi Michael,

Here's an article that may help you troubleshoot the ammeter (scroll down a bit to find the ammeter section):

http://www.lbfun.com/warehouse/tech_info/gauges%20&%20instruments/Troubleshooting%20gauges.pdf

It doesn't show up as a link for some reason, just copy and paste the URL into your browser.

Joe