Verify defect fuel sending unit

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13matsc

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Mats
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C2500
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350
Hi guys,

Original dual tank setup. Right side tank fuel gauge peaks at 3 o clock when selecting that tank. Removed the chassis ground and worked everything with the wire brush, then reattached. Still same problem. This verifies that the fuel sending unit inside the tank is faulty? Check my picture to see if the ground cable i worked on.

Left hand side works as it should. Switch, the switching valve and the resitor on the gauge itself should be OK?

Would like to be as certain as i could before dropping that tank, does not look like a fun job.
 

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Grit dog

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No expert but there’s a ton of info on here if you search. 3:00 position = open circuit to gauge iirc. 9:00 position = grounded out.
One suggestion though, I believe it’s easier to remove (or at least unbolt and slide back) the bed. Unless you have nothing or no one to help lift or slide the bed.
Just my opinion. Also makes it easy to remove both senders, inspect , clean, fix grounds etc.
 

fast 99

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The hoses are a PITA. Either unbolt bed as described above or back 4 cab bolts and block it up. I tried unbolting beds on a couple, but the carriage bolts just spun. Was less work to jack the cab up.
 

Ricko1966

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IMHO pulling the bed or cab to change a tank is a bunch of extra work. I always have to drill the heads off the bed bolts. I'd unbolt the tank,brackets and all drop it far enough to reach over with a pair of compound leverage cutters and cut the hoses in the metal,use new hose going back in. @fast 99 how did you deal with the spinning cab bolts? I have a feeling that's going to be a problem I have in the near future.
 

13matsc

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Mats
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1985
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C2500
Engine Size
350
Thanks. Looks like dropping the tank is the best alternative for me, if needed. I will be checking the wires to and from the sending unit (if I can find them).

Pink wire from the dash, through the firewall and all the way back to the tank switching valve? From there it changes to tan, and then goes to each tank sending unit?

85 model with factory dual tanks.
Weird that the sending units are placed in such a place - difficult to reach, yet open to all the elements.
 

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