[mowerman]

I have a 1974 Chevy c10 and the gauge doesn't move. Not sure what to replace. Should I replace the float or the sending unit or is there something else I should do?

 

[406Rich]

a few ways to test fuel gauges...

disconnect the sending unit at the tank... the gauge should go all the way one direction...

ground the wire you remove from the sending unit.. that you have verified is the gauge wire to the tank or sending unit .. the gauge should swing all the way the other direction...

this verifies the gauge and wiring is working..

if when you disconnect the sending unit.. and the gauge goes one direction.. and when you ground the wire to the tank.. it does not move all the way the other direction.. try a different ground ... if you have a bad ground at the tank.. it won't cause the gauge to swing..


this problem could be at the instrument cluster voltage regulator or the dash board ground connection.....

 

[cfjfisher]

What he said

 

[mowerman]

It already stays at full so do I still need test it?

 

[Blue Goose]

single or dual tanks?

 

[mowerman]

It is a single

 

[406Rich]

So what happens when you disconnect the ground wire Mowerman..?

 

[mowerman]

Haven't tried yet I'm in high school so it may be a while but I'll try to get to it when I get home.

 

[cfjfisher]

We'll have to wait till you pull the wire off to know what you need to do next

 

[mowerman]

So do I have to take the uint out of the tank or just disconnect the wire and is there one wire or more coming off the unit?

 

[cfjfisher]

Just disconnect the wire from the tank. First look at the gauge, disconnect the wire and see if there is a differance. It should go to empty. Then ground the wire and it should go to full. If all this happens your sending unit is bad. If nothing happens chances are you gauge is bad OR a bad wire .. Good Luck