Re: matthew looking for diagram to bring 12 volts to batt from truck
If the truck side +12V does not have voltage present, There could be certain conditions that affect this.
1. Test with truck running. Some vehicles must be running to have +12V present Other vehicles may be hot at all times. Test all key positions as needed
2. Fuse. Some vehicles need a fuse to be installed to activate this pin. The fuse box may have a dummy blank in the appropriate fuse holder. Replace per vehicle recommendation. The Owners manual may list the fuse but the blank will be installed from the factory.
3. Bad fuse. If a fuse is present and you are sure you tested the key positions (run/accessory/off etc) Try replacing the fuse. sometimes a fuse could be defective or blown even if it does not look bad.
Get a 7way testing plug. Make sure it tests all positions. It will have 6 lights. This will make it much easier to test the plug. An 4 and 7 way tester example
https://www.northerntool.com/shop/tools/product_200466892_200466892