I know you can take the sending unit apart to clean terminal on the top part (I've searched and read through old posts) but nobody has mentioned if corrosion at the bottom on the sending unit causes the idiot light not to work, and mine ain't working . I'm trying to use an simple two terminal aftermarket external "red" push-in type light that I've installed in my dash (not using the stock Fuel gauge, it's a smaller VDO unit though). I've got the black wire from the fuel tank sender going to one side of it and a ground wire going to the other but it's not coming on.... so I assume there's a problem with my sending unit. Would like to take it apart and save myself $100 if possible.

Doug C

I believe the low fuel warning light portion of the original sending unit is a switched ground. You need to provide +12v to the other side of the bulb for it to turn on.

Try doing a continuity test between your wire and ground. I believe you will see that the sending unit does indeed switch the ground leg for the bulb.

good luck

So let me get this straight, you think that what I actually have now is 2 grounds going to that light..? OK, I think I see how that could be. But wasn't that black wire originally just going into the back of a one terminal stock light socket, then that metal socket was gounded to the original gauge unit when installed?

I assume I need switched power then, right? Yet another reason to install an additional fuse panel..

Doug C