Gas Gauge Question

I have just rewired my '64 Econo and have most things working, however the gas gauge has never worked since I've owned it. I have a new sending unit and of course all new wire. (The gauge never actually worked but used to come up to about a quarter of a tank from empty when the ignition was on - prior to my rewire.)

I've never tested a gauge before but I hooked a 12v line to one of the terminals and grounded the other, but no movement of the needle. (I reversed the contacts as well, but no luck.) I also have another gas gauge from a parts van I had, but again no difference when I tried to test that one as well. So either I'm testing it wrong or both gauges are bad, and either scenario is possible.

Any tips? Thanks!

About the easiest way to test a fuel gauge (or just about any guage for that matter) is to hook +12V to one terminal. Take a test light hooked up to the ground of the same power source and put the tip on the other terminal of the gauge. The guage should read about half (more or less depending on specs). They generally do not like a full 12V applied across them as they are resistance based.

Thanks Mopar. I tried what you suggested, with both gauges, but no luck. I guess neither one is any good and I need to look for another. Appreciate your help!

I may have a NOS fuel gauge. I'll look around and see if I can find it.

This is from another thread, might help

https://vintage-vans.forumotion.com/t14006-fuel-gauge-sender-diagnostics?highlight=fuel+guage+testing

Thanks guys! I'll check out the thread Magic Bus posted and see if I have any luck before I give up on these fuel gauges.

You have to becareful on Ford gauges. They can't take the full twelve volts. That will fry them. Believe me. I have a bunch of them that I have cooked. The feed from the sending unit runs through the voltage regulator on the back of the instrument cluster. You also don't want to power up your cluster without a good ground hooked up. I burned up my gauges and sending unit this way. I finally got my temp gauge back but still don't have a fuel gauge. I need to drop my tank again and just haven't done it.

Duane at the Mid South Old Econoline Nationals in Arkansas