7 pin trailer connector - no 12 volt for charging

[ugh]

I took a tester and tested the 7 pin trailer connecter. All pins worked except for number 4 12 volt charger. Is there something wrong or do I need to do something to turn it on to test it? Like put it in gear or what? The truck was running in parked when I tested it.

2001 F250 5.4 RWD

[The_Texan]

Check the fuse panel under the hood. That is where the 12v originates and usually the manufacturer either does not hook up the wire, but it is there in the bundle, or they do not place a fuse in the holder or both.