Fuel gage 73 chevy c10

[hatzie]

Originally Posted by FrankSando

It's a 73 chevy pick up as I posted at the beginning
Thank-you for all the help

The basic single tank sender circuit is the same from 73-91 (the 73-86 CK and the 87-91 RV trucks). I edited the picture to expand when you click on it and touched up the rheostat so it clearly shows that both ends are not connected.
Really it's pretty much unchanged since the 1940's with two minor changes. The older trucks used a 30Ω sender vs the newer 90Ω sender and 6v electrical system gave way to 12v on the newer rigs... I believe one changed before the other in the mid 1960's but I don't remember which one or which year(s). The broad strokes of how the gauge works are the same tho.

On the 1977ish and later rigs you'll notice the needle sweeps faster from 1/2 - E than it does from F - 1/2 and it drops really fast from around 1/4 - E. You are not imagining this.

GM changed the sender rheostats on most of their vehicles around 1977 to weight the needle sweep to point to near full longer. If I can find the Chevrolet Service News article about this I'll scan it and post it. Replacement senders rheostat windings are likely weighted the same as the newer units.