well, after a lot of internet scouring on other web pages, I have found out a few things.
The stock resister is 127 ohms. you can get them from new boyz square body, OR from digikey and mouser as stated above. I have verified that mine will work with the correct resistor after getting one of my highschoolers smart buddies to put some resistors he had together to make 127ish ohms. when done, the 9v battery registerd 9v on the gauge.
Normal routing when looking at back of gauge is
ground top terminal
sender to left
nothing to right.
Sender attaches to left, gets resisted, and then activate the right terminal. If you want to test your gauge, you check ohms between right and ground and its like 120ish, or put 9v battery to ground and right terminal, and you should get full sweep. At least then you should be able to know if your stock resistor has failed. Or check ohms between right and left, which should be 127
