Guys,
Scout troop just bought a larger trailer, so I need to convert from 4way to 7 way system. Guy that is setting up vehicle plans to order a pig tail tha plugs into the white plug pictured below, but I am pretty sure that the 2000s were not prewired. That said, can anyone confirm purpose of plug pictured below. Also, any suggestions for adding a controller tooneof th older models. I searched, but most posts were for newer model years.
Thx,
Mark
Not to criticize the setup guy...but if he uses this connector he's connecting to either the power mirror system or the tilt/telescopic steering wheel. Doesn't look like either are installed in your LC.

to the guy. Were you in Idaho, we'd be done in an hour or 2.
Cannot see the back of the connector, but if 5 regular wires are going in, it's the t/t steering column. If instead there are 7 wires connected (4 that are cabled together with a shield + 3 unshielded wires, it's for the remote controlled mirror system.
Correct connection is to use the green/white wire connected to the brake switch...that should connect to one side of a relay coil with the other side of the coil grounded. Relay should be rated around 30A and I'd fuse the wire from switch to relay coil for 10A.
Relay normally-open contacts go to an always-on +12V source on one side and the controller on the other....I connect mine directly to the battery with a 40A circuit breaker and to the brake controller input , and that's for a dual axle horse trailer (4 brakes total).
To connect to the controller, the guy buys a cable for the controller with unterminted wires on the truck end and a connector to the controller on the other end.
All connections are soldered and insulated w/ heat-shrink, or crimped with tubular or brazed-butt crimp splices using a ratcheting crimp tool...i.e., crimp tool will not release until enough pressure is made to assure a gas-tight connection. If he's using Scotch-Loc terminals, immediate castration would be in order.
That said...unless the guy is perfectly competent in wiring in a controller, do not let him screw with your truck.

Errors can cause ecm issues or worse (price a new harness

).
Based on your post, I'd get your truck to a competent trailer shop and not let the guy intercourse with it...I've seen and repaired enough aircraft electrical installations done by morons...fixing mistakes pays VERY well, and the parts pricing is similar to what Toy asks...though Toy parts are much harder to source.
Lighting connections should go through a good quality trailer adapter, as Toy has had issues with the oem controller you'll find by removing the jack cover and looking a little aft of that...lots of threads here.
hth and let us know what happens.
Steve