I got tired of having to kneel and get under the rear bumper to connect trailer wiring, so I decided to create a wiring extension that would be mounted in the bumper cover, and would connect into the OEM plug.
I ordered these parts off Amazon:
1. Hopkins 40974 Multi-Tow 7 Blade and 4 Flat Connector; this is identical to OEM plugs on the Tacoma, Tundra, etc. Seems to be very low profile.
2. Hopkins 40985 Universal Multi-Tow Harness Connector; this plugs into the above connector and has 7 wires that need to be connected to the vehicle.
3. Reese Towpower 74127 Plastic 7-Way Flat Blade Trailer End Connector; I'll connect the wires from item 2 to this male connector and plug it into the OEM hitch wiring.
And here is how it went!
The wiring room that arrived wasn't the greatest (just oversized split loom over wires) so I cleaned it up a bit:
I made the necessary connections and covered the parts that would be assembled in silicone to add a bit more water resistance:
Assembled and added a bit more silicone on the exterior:
Cut a mounting template from cardboard, attached it on the bumper cover where I wanted the connectors to go. I initially wanted to place these on the driver's side, but decided that with the exhaust terminating in more or less the exact spot I wanted the connector, there was a risk of melting wires from exhaust heat, and I'd use the passenger side instead.
Two of these metal clips are what holds the connector in place. The bumper cover is very thick (around 3-4mm), so getting these to clip in was a nightmare. I had to slightly bend them to give myself a bit more "material room," and then installed them from the back after sliding the connector through the cut-out hole.
I took the OEM connector off the bracket it was mounted on, clipped in my extension, and zap-strapped both pieces.
I then tucked away all wiring (including the joined connectors) behind the bumper cover, secured things with a few more zap straps, and flipped the original connector mounting bracket around to get it out of the way. There is about 5mm of clearance between the flipped bracket and my 33" spare tire.
This is the end result:
I tested everything several times throughout the process and at the very end. Working great! Perhaps not the most aesthetically pleasant spot for the connectors, but it sure does make things a lot more convenient. No more having to use 7-pin to 4-pin adapters, and no more climbing under the bumper.