1972 Chevy C20 Fuel Gauge--Help!!

[MurphyGirl]

Hey all,

Needing some help here. Our 72 Chevy's fuel gauge only reads full. Guy we bought it from said it was working but quit. I need some troubleshooting tips on how to repair this, or should I just take it to a professional? Just had to run gas to my 16 year old who drives it because he ran out. I am a nice mom, but not nice enough to do this often. Just want it fixed. Any tips would be greatly appreciated!

Murphy Girl

[crazychevyc10]

It might be the fuel pump floater. Mine stop working too. maybe others can chime in on this too

[1972BlueC20]

With the key in the run position, pull the tan wire that runs to the sending unit on the fuel tank behind the seat off. If the gas gauge doesn't move at all with that wire pulled off then you need to most likely replace the fuel gauge. I just went through this with my 72. I ended up changing the gauge and got a new wire that runs from the sending unit to the fuse panel. I also replaced the sending unit first, because I was told it may be the sending unit or float. It ended up being the gauge itself. It works perfect now. Also check your ground that runs to the gauge cluster.

[undertaker72]

I second on checking your ground

[Roadster_g]

I had replaced my sending unit and guage still wouldn't work. I foolishly didn't check with an ohm meter first.
My problem ended up being a $10 resistor that sits behind the fuel guage. Now works fine.
greg

1972 GMC 4X4

[70LonghornCST]

If the gauge reads full, there are three possible checks for you:

1. a cracked/cut wire is grounding out along the way from the fuel tank sending unit to the fuse box.
As stated before, it's the brown wire.

2. the flat resistor behind the gauge is out and needs replacing.

3. the float is stuck in the up position. (I'd check this last as it's the least likely possibility).

Keep us posted.