Rcimp,
You said you were going to take them to work and do a bench test...is this were they don't want to 'do their thing'. Sometimes hooking stuff up with a maze of jumpers and power supplies get things more confused than just doing it in the truck.
Break the problem into two parts. The sending unit is easy. If you connect a ohmmeter between the flange (ground) and the terminal then move the float up and down, the meter should move. The sender has 0 to 30 ohms of resistance. Any meter scale should move but the K1 scale should read much closer...if the needle moves, the sender is good. This can be done on the workbench.
The second item is the gauge...duh! This procedure was outlined above before. If you power the gauge, ground its case to common on that same power source the gauge should read FULL. If you attach a jumper to the sending unit terminal on the back of the gauge and touch it to the same ground the case is hooked to, the gauge should swing to EMPTY.
If this doesn't work, you are doing it incorrectly or the gauge is no good. I'm pretty sure you will get the sender to work. This is a simple test if you are careful about getting good contact from your temporary wiring.
I'll bet you could attach your meter to the power terminal and the sending unit terminal of the fuel gauge and check for continuity (resistance scale-K) too. I don't know what the resistance would be, but it will move the needle on one of the scales for sure. This should also work between the power terminal and a shiny spot on the case. Now you can do all the troubleshooting with just a simple multi-meter...no jumpers or power supplies. Let us know what happens.
Stuart
