Curt Class III Trailer Hitch and Wiring Installation on the 2G Acura RDX

Gather the Curt #13130 receiver, the #57008 harness, and, if you want the cleaner look, the #21728 tube cover. All three are matched to this chassis. Read the torque and hardware callouts on the Curt instruction sheet before touching the vehicle, but plan to deviate from the stated torque as noted in a later step. Keep in mind the roughly 1500 lb rating when sizing whatever you intend to pull.

The captive weld-nuts on the frame carry a zinc coating that will fight every bolt you try to start; forcing a fastener here risks a stripped, botched thread. Clean each nut first with a tap sized M12 x 1.25. Flood the threads with penetrating oil, then run the tap in a few turns and back it out repeatedly so the coating, rust, and debris clear rather than pack. A brass brush spun in a drill helps knock loose surface buildup beforehand, but on this frame the tap still does the real work. Have the tap in hand before you begin rather than discovering the need mid-install.

Each frame rail has a step at the rear holes, and the factory Acura hitch uses spacers there for a reason: without them the top of the receiver tube contacts and lifts the lower bumper. Stack stainless fender washers of about 3 mm thickness at the two rear bolts to space the tube down. One washer per side may not be enough. In the follow-up discussion the writer needed to double them up for eight washers total to nearly clear a bumper that had its own upward contour, so test-fit and add washers until the tube no longer pushes on the fascia.

Support the hitch up to the frame and thread the supplied bolts, with your washer spacers at the rear positions, into the freshly chased weld-nuts by hand. Grease each bolt before it goes in. Start all four before snugging any of them so the receiver can shift into alignment; running one bolt fully home early can bind the others.

The Curt instructions call for a torque that proved too high on this hardware: the writer stripped a handle-nut before even reaching 100 lbf-ft and twisted a second fastener trying for 110 lbf-ft. A more reliable approach, confirmed in the thread, is about 60 lbf-ft on all four bolts with the threads well greased, which yields effective clamp load without destroying the fasteners. This is a correction to the printed spec, applied because the published figure caused failures during the actual install.

Work from the rear driver-side interior access panel and feed the #57008 harness down into the spare-tire cavity. You do not need to strip out every trim piece the Curt video removes; a straightened coat hanger pushed through and taped to the wires lets you draw them through with minimal disassembly.

Locate the factory trailer harness plug and mate the Curt connector to it. The connection is made largely by feel in a tight space, so register the orientation of the plug before you commit so you seat it correctly on the first try rather than fighting it blind.

Zip-tie the harness module and dress the wiring so nothing rattles or chafes; stowing it with the spare is fine if you tow rarely. Slide on the #21728 tube cover for a finished appearance when the receiver is empty. After the first few trips under load, return and re-check the mounting torque, since initial use can settle the joint.