ammeter pegging

[Don W.]

I was out for a long drive on Sunday. My ammeter needle would run at zero and then snap to right to +40 several times per minute. Any thoughts or normal? thanks...Don

[Jim T.]

Re: ammeter pegging

Is your car a 68 or 69? 1968 was the last Corvette with external voltage regulator mounted on fender well and 1969 first year for voltage regulator in the alternator? On the rear of a 1969 alternator there is a place you can touch a tab with a screwdriver and verify the alternator is working. This function bypasses the regulation of the internal voltage regulator.
The 69 voltage regulator is not difficult to replace. A toothpick or something similiar will hold the brushes retracted.

[Don W.]

Re: ammeter pegging

Mine is a '69 and everything seems to be working fine. The battery stays charged and drove it for 3 hours on Sunday...Don

[Richard M.]

Re: ammeter pegging

The meter is actually a current sensing sensitive voltmeter. It senses the differential voltage between the battery voltage at the starter and the load out at the horn relay buss bar.

It's possible that you have a defective meter, but it's also possible that your connections at the source and load points have corrosion and are connecting intermittently and causing your meter to deflect intermittently. Check your connections and clean if needed. The wiring passes through a body connector so possible corrosion there too. I'm not sure where that connector is on a '69.

[Paul J.]

Re: ammeter pegging

Don, it could also be a short somewhere in the wiring, but first I would check the voltage regulator.

Paul