hi guys.

im getting ready to put a new gas tank/sending unit in my 72 ss. heres my problem.. where is the wire that connects to the sending unit. it is missing i think.. i see some sort of connector by the rear license plate. does a wire connect from there to the sending unit... i also see a wire right above the gas tank used to be which is screwed directly to the trunk floor..this is the ground wire right???
very unsure how this hooks up...

Please Help...

Tom

Your right on track infact the wire is on top off tank hidden buy the trunk pan the outher one is ground.Drop tank and away you go simple have fun Don.

Very simple device, all it is, is an electric rheostat in the simplest form. There's 2 wires, the ground wire that goes from the sender and gets screwed into the body sheet metal (should be black). The other is the sender's output which leads back to the dash. (should be tan). The wire coming off the sender meets just below the rear license plate to a rubber boot connector, that connects to the other half of the connector/wire that leads to the rear trunk harness and ultimately the dash.

To make sure it works...

If the tank is empty you should have 0 ohms at the sender wire with respect to chassis ground.

About 45 ohms at half full at the sender wire with respect to chassis ground.


About 90 ohms at full at the sender wire with respect to chassis ground.


Joe

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"Yes, I'm still workin' on those Chevelle radio pages!"

Coppertop,

I have the sending unit out of my '68. The sending unit itself reads "90 OHMS" on the side of it. Can I check the unit with a multimeter, by just grounding it, and carefully move the float up/down ?

Thanks for your time,

Kent
'68 Malibu ZZ502/502

68,

Here's how I'd do it. You've got a multimeter, set it for OHMS, connect one of the meter's lead to the ground wire coming out of the sending unit, connect the other meter wire to the other wire coming out of the sending unit (the sender wire).

Now hold the sender like it would naturally be in the tank with the float down. Let the float droop. This will imitate empty, you should see close to zero ohms or continuity.

Now push up on the sender's float, you should slowly see the resistance go up until you reach "full" or close to 90 ohms.

An analog meter would be a better choice as you can see if the needle on the meter smoothly moves, as a digital meter will be "jumpy" reading different digits and will be hard to tell if the sender has bad windings. If you're really still at different postions, the digital meter should level off.

Chances are if you get correct readings at the three points (these are approximate)

FULL 90 ohms
HALF 45 ohms
EMPTY 0 ohms

The sender is good. Play around with it and see if things look okay. http://www.chevelles.com/forum/wink.gif

Don't try to hook any power to it as a spark would be not good around something that has gas fumes! http://www.chevelles.com/forum/redface.gif

Joe


http://www.chevelles.com/forum/wink.gif


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"Yes, I'm still workin' on those Chevelle radio pages!"

Coopertop,

Thank you. http://www.chevelles.com/forum/smile.gif

Kent
'68 Malibu ZZ502/502