Wiring a 4 Pole to 7 Pole Adapter on a 2004 Chevy Colorado

Expert Reply:

The 4th wire on 4 Pole to 7 Pole Adapter, part # 30717, can be used for multiple purposes. It can be an auxiliary power source, it can be a reverse lock-out for hydraulic brakes, and it can be the wire for reverse lights on the trailer. Depending on what the trailer needs, you would wire it to one of these.

If not needed, it can be taped up back to the harness out of the way, but it will still be there if needed in the future. We have a similar part # ETBC7 that we have several videos including this part in the install. I will add a link to that product page so you can check out the videos. They should give you an idea of how the wiring works. We typically recommend this part as it also has a 4 Pole built in so you can use a 4 pole trailer without having to disconnect it from the the 7 pole harness.

expert reply by: Patrick B