gauge sender (gas tank)

[The dream]

When I got my truck, the guy I bought it from told me that the fuel gauge didn't work. He told me that he already changed the "floater's" in the tank and still couldn't get it to work. Ive noticed that the Fuel gauge does move, but it moves way across FULL. It sits on Full when the truck is off.
 
So i started to look around for a new gauge sender and i found this: "Sunpro/240 Ohm Empty and 33 Ohm Full Fuel Level Sender for Fuel Level Gauge and 5 to 26 in. Deep Tanks"... would this work with the truck? (78 K20 with 2 tanks) 

Is it possible that the previous owner used another kind of sender with different Ohm readings that is not for the existing gauge and there for giving me a reading in a different position in the gauge? 

PS I cant reach the guy that sold me the truck to ask him any questions about the truck.

[frogman68]

Yes you can use it but you will need to drill a new hole for it
Believe its around a 1 1/2 inch hole

[The dream]

So that is the right "ohm" range? do you know of a better brand/part that would fit without drilling?

[frogman68]

So that is the right "ohm" range? do you know of a better brand/part that would fit without drilling?

Oem is going to be it the fuel sender is built into your original

[Captkaos]

The sunpro you listed is not the correct Ohms for factory guages.  GM is 0-90Ohm.
Off position should be ingored.  Where is it when the truck is on?

[frogman68]

The sunpro you listed is not the correct Ohms for factory guages.  GM is 0-90Ohm.
Off position should be ingored.  Where is it when the truck is on?

Oppps thats right I used the sunpro gage instead of the original

[Irish_Alley]

I'm kind of shocked that if your gauge doesn't work some one would think that both floater would have gone bad at the same time, nothing against you but against the po. but i guess i v seen worse. after you check your dash for the right ohms i would go to a yard and pick one up probably be cheaper and look better than an add on from the parts store. unless you do them all

[oldwhity]

When I got my GMC in March, the only gauge that worked was the speedo and the PO installed an aftermarket temp guage in the dash where there is no gauge . Two weeks ago I took out the cluster and began to troubleshoot. Apparently the the gauges lost contact with the printed circuit sheet on the back of the cluster. On the back of each gauge there are studs that go through the rear of the cluster. Those studs are held by clips that contact the circuit sheet. I just cleaned the contact surface on the sheet and rebent the clips to ensure contact and they've been working ever since. Now I don't have to guess when I should fill up with gas.lol

Hope this helps. I figure it'd be worth a shot before you buy new gauges.