1959 battery gauge

[Robert D.]

i am putting my dash back together and my batery gauge has a large what looks like a resistor on one of the conectors. i can't remember where the other end goes it has a round connector on it like it goes on one of the connector posts. appreciate some in put on this one.
thanx
bob

[Ed Jennings]

Re: 1959 battery gauge

That is a capacitor. I seem to remember that it fits across the gauge connections, but check the radio section of the AIM to be sure.

[Michael D.]

Re: 1959 battery gauge

one end connects to the instrument cluster

[Dennis A.]

Re: 1959 battery gauge

The brown paper wrapped capacitor is installed having the "black" band end grounded to the instrument panel.

[Jack H.]

FYI...

You are correct about which end of the headlight capacitor connects where, but here's a bit more 'trivia'. The wax-foil capacitor we commonly call the 'ammeter' capacitor (Delco Remy 7275068) is installed to thwart 'clicking' noise interference in the radio due to turning the headlights on/off and changing dimmer position (hi beam/low beam). Unless, you're driving at night in the boondocks under AM 'fringe' reception conditions you'll never notice its absense!

Instead of tooling a separate HL switch for Corvette (passenger cars had stamped sheet metal body components that acted as a Gaussian shield for the wires running to the headlights), this RF cap was tacked onto the ammeter because it was essentially 'watching' the entire electrical system and that was a convenient/cost-effective alternate location for it.

YES, the body of the capacitor has a black line on one end, but this is a non-polar component and that line does NOT indicate which end of the cap should be grounded. It indicates which end of the capacitor's internal foil 'plates' is located at the top of the capacitor (just below the paper label and wax insulation).

The capacitor will work just as well it it's connected 'backwards' as it does when connected in the standard (correct, factory original) position Dennis describes. The reason for the labeling and installation convention is this:

What happens if the cap should rub/vibrate and abbrade the component's wax + paper outer insulation? Eventually, you could get metal to metal contact between the top storage 'plate' of the capacitor and the metal back of the instrument cluster....

If the cap is installed such that the top plate IS the lead wire end that's connected to the instrument cluster (ground), then there's no harm done. If connected in the opposite fashion, you'd essentially peg one side of the ammeter to ground!

But, this consideration isn't a panache. If the body of the cap is vibrating and rubbing against the back of the instrument cluster with sufficient force to wear through the wax/paper insulation of the body of the cap, it's only a matter of time before it also wears through the first foil plate, the inter-plate dielectric, and the opposite plate (the lead wire connecting to the ammeter) ALSO becomes short circuited....

So, the identification of which lead wire connects to the capacitor's outer/upper plate is nice to know and the installation convention has a modest safety impact, but it's NOT a bulletproof safeguard!

[Dennis A.]

Re: FYI...

Jack...

I understand that the capacitor's other end wire may attach to either the "RED" or "Black" wire and still function as you outlined also.

[Michael D.]

Re: FYI...

jack answer that last question. i have seen them both ways