62 corvette fuel guage
 

I recently replaced the dash pad in my corvette and when I got the =
> instrument panel back in and wired, the fuel gauge pegs to past full as =
> soon as I turn the key to on. I have a wiring diagram and I am sure I =
> have the correct two wires tied to the guage. I noticed a piece of =
> rubber or something between the two terminals and below the nuts behind =
> the gauge and wondered if I might have damaged that when I reinstalled =
> the wires and nuts or If I may have somehow put a screw through the =
> brown wire going to the gas tank when reinstalling the left kick panel. =
> I do not have a diagram for the gauge so do not know what may be causing =
> this.
Thanks

If the tan wire going to the tank is not connected (open) the gauge will peg full. If that wire is shorted to ground, the gauge will read empty. Here's a gauge diagram, if that helps.

https://cimg3.ibsrv.net/gimg/www.cor...20b1ab093a.jpg

I had the pink and brown wires reversed to start with and the needle pegged. I then switched the pink and brown wire to the correct terminals and the needle still pegs. I checked the wiring and does not appear there is an open circuit. Could I have damaged the gauge by putting the hot lead to the side the tank sender should have been?

I believe you have full a ground going on, not an open circuit.

If you damaged the insulators at the studs on the back of the gauge, or twisted the studs sideways so they contact the gauge body where they pass through the holes, you would get this effect.

Doug

If the tan wire on the gauge's "S" terminal is open it will read full...if you ground that terminal the gauge should read empty.

Here is the JohnZ article with the "quick and dirty" checks a few paragraphs in on the first page:

Disconnect the tan wire at the back of the gauge, read with an ohmmeter from the tan wire connector to ground. You should get between 0 and 30 ohms. If you get anything significantly over 30 ohms (including an open circuit, you either have an open wire to the sender, or the sender is open either at the connection or internally. To get correct deflection of the gauge, that wire has to read between zero and thirty ohms depending on how much gas is in the tank.

Pay attention to what I (and Frankie) told you. It is opposite of what you would think, an open wire to the sending unit causes FULL deflection, a short on that wire causes an empty reading. So..... If you short that tan wire to ground with it connected to the gauge, you should get an empty reading. With that information, you can eliminate or determine the sending unit and wiring as a problem.


DON"T SHORT THE PINK WIRE TO GROUND, it's battery voltage.

Thanks Frankie! I'm printing off all these old articles by John, that you and others post here. I missed them the 1st time around and find them way more helpful than the factory SR-12 manual.

Someone ought to make a book out of the combined articles for us rookies.

Butch

I've never once gone wrong following John's online advice or his articles - I have a ton of them in my digital library..
Between John, Tom Parsons, DZvette and some others all of our C1 cars are better for their experience and sharing..

Something like these at the top of the C1/C2 forum?

https://www.corvetteforum.com/forums...aq-thread.html

https://www.corvetteforum.com/forums...ky-thread.html

Must be a two coil gauge. Thanks for the clarification.

Doug

And just to add to the confusion C1 and C2 fuel gauge/sending units work the same....

C2s are entirely different....nobody knows why...

Exactly! Please don't tell me they're already up there and I just missed them. :banghead:

Regardless, I've saved them to my desktop so I'll have them going forward as this looks like some very good reading. Thank you 65GGvert!

Butch

Sorry, but they've been there for years

For some reason C2's run a separate 12-volt lead back to the sending unit. Somewhere along the line someone must have thought that was better

Well, I learned many things today. :cheers:

BH