Towing: trailer tow backup lights no working

[Beavrz]

Howdy Forum!

I'm trying to chase down a frustrating issue on my 2019 2500. Recently noticed that the backup lights on my travel trailer no longer activate when backing.

1: I first hooked up a DC bench power supply and checked every pin in the trailer side 7-way. All worked fine.
2: no errors or intermittent alerts from the trailer towing module

Naturally suggests that it's not a trailer side issue. Moving on to the truck

3: To save guesswork I bought a 7-pin plug and went about testing all functions. Everything checks out...EXCEPT Backup Lights.

4: checked fuses. F28 and F29 check out. F30 also good. Just in case the might be stealth-blown, I even swapped in new ones ...no change.

At this point I can pretty confidently say no 12v is being put to the center pin on the 7-way socket on the truck side.

Anyone here experienced this before or have suggestions?

 

[flan]

Wires going onto the back of the plug have had issues in the past, I’d poke around back there.

 

[Beavrz]

outstanding suggestion flan!

dropped the spare, unplugged the trailer plug and discovered....that the center pin was actually not seated properly, but in fact was bent outwards so no contact was made. bent it back and BOOM success!
Clearly installed hastily at the factory!

thanks a bunch

 

[flan]

outstanding suggestion flan!

dropped the spare, unplugged the trailer plug and discovered....that the center pin was actually not seated properly, but in fact was bent outwards so no contact was made. bent it back and BOOM success!
Clearly installed hastily at the factory!

thanks a bunch

Glad it was solved fairly easily.