Power to gas gauge ??

Unknown

I still have the electrolock on my 29 Hudson. I have been trying to get the new gas sending unit to work.The Hudson manual shows the wiring for the electrolock as 4 sides one having nothing. The right side going to coil (in my case the - side) and (HOT) when the key is on. The left side to battery and the bottom to coil ( in my case the + side) and gas gauge NOT HOT)) when key is on. I have replaced the wiring to the coil and it did run when I parked it. The gas gauge never did work because the sending unit was bad. The oil gauge did work but I seem to remember only trying it when it was running. Question is does the car have to be running for the gas gauge to work or do I have something wrong ? I am trying to see if it works before installing it and the tank. Thanks Ron