Ammeter from which year

[Sven010]

Hello,

I´ve got a modified ammeter gauge (front original look from 1947 and rear electrical side from maybe 60´s) on my Chevrolet 3800. Due to another electrical problem the gauge was burned. I want to purchase a new gauge and modify it to old look like it was done bfefore. Does anybody know the year of this gauge (see rearside).


Thank you for any idea!

Sven

[ray_mcavoy]

Hi Sven,

That looks like the inner workings from a 1964 - 1966 Chevy truck ammeter.

As you may already know, they were originally designed to be wired in parallel with a shunt. And in the 64-66 trucks, the shunt was simply the 5-foot or so long section of 12ga wire running from the positive battery terminal over to the main power distribution point (screw terminals on the horn relay).

With that configuration, the majority of the current flows through the shunt wire and only a small fraction goes through the coil on the back of the meter movement itself. I've seen them burn up like that in 64-66 trucks if the shunt wire gets corroded or disconnected and forces the current to go through the meter coil instead.

I'd recommend adding a 4 Amp fuse to each of the meter lead-in wires near where they make their connections to each end of the shunt. Like GM did with the 67-72 trucks. That provides protection to both the gauge assembly and it's lead-in wires in the event of a short to ground or overload due to a problem with the shunt.

[Sven010]

Thank you very much for your help!!!
That´s right, the wiring is like your description.

Many parts/components of my truck are from 60´s but I wasn´t shure from what year I had to purchase the ammeter. Now, with your help I could order a spare part.

Something happend during the long trip (with some problems) from Texas to Germany. I will add some fuses like you suggested.

Thank you very much again for your help!

Best regards,

Sven

[ray_mcavoy]

You're welcome Sven!

That's good to know that they wired the ammeter up correctly. Chances are, a connection at one end of the shunt loosened up during transit. That would result in all of the charging system current trying to flow through the coil on the gauge, causing it to burn up like it did.

For troubleshooting purposes, you should be able to start & run the truck with the ammeter disconnected. And other than not being able to view the meter reading, the charging system should still function normally. If not, that would possibly indicate a problem with the shunt wire and/or it's connections that needs to be corrected before installing the new ammeter.

[Sven010]

I will check everything before burning the new ammeter .....or truck