67-72 Chevy Truck fuel gauge diagnostics 101

[TBONE1964]

Originally Posted by jjzepplin

I went and tested the gauge.When I pull the brown wire from the fuse block the gauge reads just past the last "L" in full. Not 3 oclock.
When I ground the fuse block connection it goes to empty. When I turn the key off it slowly creeps back up.
Sender is reading 10 ohms.
I did test a spare gauge and it reads 38 ohms left pole to right pole. (just for reference)
So would the next step be to measure the gauge in the truck?
Think I will try that while waiting for response.
thank You fellas for all you do.

"I went and tested the gauge.When I pull the brown wire from the fuse block the gauge reads just past the last "L" in full. Not 3 oclock."

That is strange and would make me think there is something wrong wiith the gauge resistor or the gauge itself.

"Sender is reading 10 ohms."

You are referring to sending unit in the tank, correct? If it is accurate, I would believe you have or should have almost an 1/8 of a tank of fuel.

"I did test a spare gauge and it reads 38 ohms left pole to right pole. (just for reference)"

Did you do this to the gauge in the dash as well? If not, try it but unplug the connector from the cluster so there is no back feed.

Sorry but I have to log off and get to the Airport for El Paso. I will check back on this soon.

We are going to figure this out and get your gauge working properly

Take care,
Tom