EVAP vent valve issue

Had a vent valve stuck open when testing so i purchased a new one. Tested the new one and it worked good on the bench. Tested for 12 volts across connector in back of truck with key in and was good. Connected the new valve and cycled key on and off and NO CLICK. Fabricated a 12 volt tail light to test under load and when touching connector, it would not light up. Just had this surface 12 volts with nothing connected. Wht should I do next? I thought about running a wire from the battery negative terminal to the back with. known good ground and try touching the other lead to the positive side of the connector and see if it lights which would tell me maybe the negative side had an issue. What do you think? Also, can not find a good schematic of the wiring going back to fuse box or PCM ANy idea what the issue could be?
Thanks,
Robert W.