spoolin01

Hello all, new owner of a 2016 RDX handed down from my Dad. Just installed a Husky 2" receiver hitch, and am on to the wiring harness. I see there are a lot of ready-to-connect harnesses available, which have some sort of isolator modules as well as the RDX-mating connector. I'm just towing a small trailer with standard rear left/right LED lighting pods. Is there some reason other than the convenience of the RDX-ready connector fitting, that I can't just wire up a simple 4-wire connector, like I've done for every other vehicle? What function do those isolator modules perform?

DCS

Acura has trailer wiring kit 08L91-TX4-200 for ~$118. The isolator or control module provides a separate fused power supply line(s) for the trailer lights so if there's a short with the trailer wiring it won't take out your car's brake/signal/running lights. There's also relays to minimize the load on your car's rear lights and connect the separated power to the trailer lights.

spoolin01

I'm wondering why it's needed for the RDX when lights for small utility trailers have historically been wired directly to the vehicle's lighting circuits? I've done that for many vehicles without problem. What's different here? If for some reason separate fusing is desired, that can be done for a lot less than what these harnesses go for.

DCS

The separate power and fusing isn't absolutely required but if there were problems with the trailer wiring it would protect the car lights from being affected. Adding a separate power and a fuse would also not add to the current load of the fuses used for the car lights. The relays in the trailer control module are needed to switch on and off the separate power to the trailer brake/signal/running lights. Depending on the current load of the trailer lights it could be possible to exceed the limit of the car fuses if a separate power and fuses aren't added.