Trailer plug wireing

[cnold]

I have a 2005 Tundra with factory tow package and want to hook up the backup lights on a travel trailer. The center pin on the 7 pin Bargman connector is normally used for that purpose. I checked for power at the center pin with the Tundra backup lights on but get nothing. Is the center pin left open or does it serve some other purpose on a Tundra?

[krodad]

I am not aware of any manufacturers setting up the center pole for back-up lights on a trailer. Generally, the center pole is an auxilliary power wire for use in battery charging, switched lighting, etc. and is sometimes hot and sometimes left dead until the end user decides to activate the auxilliary.
I used to be in the trailer mfg. industry and it is not standard to have white back-up lights. Maybe things are different now for RV type trailers, but don't expect this center pole to act in this manner unless you intentionally tap in to the reverse light circuit, and do the same on the trailer side as well, if it does indeed have back-up white lights. Make sure these function correctly and don't illuminate at any time when going down the road, or you'll get a "white light" ticket from troopers having a bad day.

[brandkd]

The center pin is hot, and used to trickle charge the battery on your travel trailer. At least that's what mine does.

[krodad]

That's actually pretty cool. I have never owned a travel trailer, but back up lights would sure as heck be handy.
I need to update my own internal knowledge base on these 7 prong plugs. Thanks for the info.

[cnold]

I was not able to pull up the diagrams for the '05 Tundra but knowing that '03 and newer models are the same helped. I see that Toyota got it right. The center pin is wired directly to the backup light relay.