C2-Bench testing NOS fuel guage & sending unit

[Andy #28359]

I have a NOS fuel guage and a NOS sending unit that are about 20 years old. I want to install these in my '65 but would like to test them both before installing. Anyone know how to test them using a power supply and the Whetstone bridge circuit without using the car? I have searched the archives but have only found "on car" tests. The sender has terminals marked "I" and "S" and a ground lug. The guage has 3 terminals with no markings.

[Wayne W.]

Re: C2-Bench testing NOS fuel guage & sending unit

The sender is very simple. There should be 90+- Ohms between the Ign terminal and the ground. There should be variable resistance from the Signal terminal to either the ground or the Ignition terminal from 0-90. The guage should have two wireswires as installed. The plug is shaped like a T. the wire that is the cap of the T is the pink or Ignition 12V. the other is the tan. If 12V is applied to the pink and you alternatly apply 0 or 12V to the tan wire, the guage should deflect full both ways.

[Andy #28359]

Re: C2-Bench testing NOS fuel guage & sending unit

Thanks Wayne. The sender checked out perfect. I will check the gauge after I figure out which terminals to test. Your reply made this very simple.