raweddle

Hello, corvette experts! The ammeter on 'baby blue', my 1967 small block convertible, has been inop since I owned it. Placing a 9 volt battery across the contact points on the back of the guage does not elicit any response. I get roughly 12 v readings from both sides of the plug (this may not mean anything) I have ordered a replacement ammeter. What is the process for changing out the guage? Thank you.

JohnZ

With some patience, you can remove the three screws that attach the "pod" containing the battery gauge and the fuel gauge to the back of the cluster can (after removing the headlight switch) and swap out the battery gauge. It helps to remove the seat first.

nassau66427

When I did mine, I disconnected the headlight switch from the cluster but left the wires attached. I also disconnected the headlight rollover switch from the cluster and left the wires attached.

Being lazy and wanting a place to sit while I swapped out the gauge, I didn't remove my seat.

I did however remove the steering wheel to make it a bit easier.

Spend some time studying JohnZ's picture. That'll give you a good idea of what you have to do. Unplugging the gauge lights first will make it a bit easier too.

You can do it from the comfort of your seat by feel. There's no need to try to scrunch yourself up under the dash.

gscott

I'm looking at the same project, thanks for the tip, I was going to remove the enire cluster.

raweddle

thank you
I will try it and wish me luck
please accept my corrected spelling for gauge
rich weddle

65 vette dude

Don't forget to disconnect the battery before you start, and put an inline 2 amp fuse on one of the wires that connects to the back of the gauge.....it will save you from having to do this job again.

jvanceh

Just a reminder, there is a capacitor attached to the screw at the 5 o'clock position that isn't shown on the above picture (at least it is present on my one owner 67 327).

KSL '67 101234

An amp gauge measures current flow of voltage. Think of amp flow like gallons per minute (GPM) in plumbing systems or cubic feet per minute (CFM) in air compressors. Think of voltage as the pressure needed to push the current or pounds per square inch (PSI).

The test you performed will indicate no reading on the amp gauge upon connecting a 9v battery to the leads as there is no current flowing through the gauge. The battery test you performed will work on a volt gauge. Be carefull as the test you performed on a functioning amp guage can permanently damage the guage.

vetsvette2002

The "Amp Gauge" on a mid year vette is actually a very sensitive differential volt meter.

wombvette

OH Boy, Here we go again. Yes, the gauge indicates amperage, but in fact is it`s a very sensitive volt meter, unlike some old car ammeters. That is why the leads both are reading 12V. Their placement within the 12V source is on two positions with some resistance between them. Any current flow makes a very small voltage differential, which this gauge picks up.

Matt Gruber

is a 61 a real ammeter?
.
on my 72 i installed a real voltmeter. BUT, next time it will be digital, as it doesn't go low enough for cranking volts, a MOST important battery check

Jim_C

The "shunt" is the #10 red wire from the starter to the horn relay. I would guess the maximum voltage drop would be on the order of a half volt for max meter deflection in either direction. Placing a 9 volt battery directly across the C2 "ammeter" would probably burn it up.
CUL Jim

dplotkin

What ever kind of meter it is (I think it does little more than indicate a difference in potential between two points), the fact is that a regular shunt type ampmeter (as used for example in most 60's Pontiacs) or a voltmeter would be far more useful.

Dan

wombvette

That's were the debate comes in, whether a volt meter is better or an ammeter, even this type of shunted ammeter.

The volt meter has no ability to indicate the battery's condition, just that it holds a certain voltage and that the alternator holds a certain voltage. The battery could be on its last leg and have no reserve capacity but still show a perfect voltage number. The ammeter has the ability to indicate battery condition by showing the length and depth of the charge. I prefer the shunted ammeter myself.

babbah

dplotkin

I don't know why their should be debate. I agree with you. The issue I suppose is which condition is most important to a motorist. Traditionally is was more important to know whether or not the generator was supplying current, probably because in the early days charging system trouble was far more commonplace what with brushes carrying all of the generator output, comutators burning and mechanical voltage regulators sticking.

Today however I agree that battery failure is more likely, at least with modern cars and to a lesser extent among our old cars perhaps using solid state regulators.

A voltage meter will provide a good idea of generator output while an ammeter will show how much current a battery is sucking from the generator, so to speak. They knew this even in the early 60's as I recently came across an ad in an old Hot Rod for a SW voltmeter exactly like the one I run in my 61 Plymouth Super-stock. So even then, when ammeters were de rigueur, SW was making voltmeters for people who wanted them.

Sorry to go on about this, I'm an old phone company guy and battery/charging systems were one of my specialties.

Dan

babbah

"Tip and Ring and an hour for lunch"

dplotkin

Yeah, that and red, orange, green, brown slate!

babbah

and 66 punch down blocks, bridging clips and 25 pair cable!! Been there, done that = LOL

rgbau140

I might start this project tonight. does anyone know the size of the heads on the 3 screws holding the pod to the cluster?