Honda CR-Z LED Rear Diffuser Reflector Light Installation

Order an LED bumper-reflector set sized for the CR-Z rear diffuser; the widely used units are branded iJDMTOY (also sold as MotoringMax and through various eBay listings). Later production runs are the better choice: they fit far more accurately, ship pre-tinted in red so no painting is needed, run brighter with a second LED strip, and carry a vendor warranty. Early batches shipped without the metal retaining clips shown in some listings, so plan to fasten the units with small screws regardless of which version you get.

Skip this step if the lenses already arrived red or smoked. To make clear lenses resemble the factory reflectors, spray the face with VHT Nite-Shades Red translucent lens paint, building two to three light coats and allowing roughly 24 hours between coats. For a darker, smoked appearance, follow with a coat of smoked lens tint and then a clear coat. Scuff the side surfaces with 400 grit paper and paint them flat black so stray light does not leak from the edges and the border reads clean. Let everything cure fully before handling.

Take out the rear tail-light housing on the side you plan to wire into, exposing the connector block behind it; the LED brake feed is the uppermost plug on the back of the housing. Removing the lower diffuser section as well is optional but makes the whole job much easier, and most installers found it worthwhile. The reflector garnishes being replaced clip in along one edge and tab into place on the other, so they release with gentle prying.

A square boss surrounds the wire exit on the back of each reflector and can foul the diffuser opening. If it interferes, trim that plastic with a rotary tool until the unit seats flush. Newer batches generally sit properly without any cutting, so test-fit first and remove only as much material as necessary.

A channel runs down behind the bumper from the tail-light area to the diffuser cavity. Feed the reflector leads up through it; a wire coat hanger with tape on the end makes a good fish, and shining a small flashlight up from beneath the car helps you locate the opening. Tape the wire off as you go so it cannot slip back down while you work. A second person on the underside end speeds this up considerably, though one person can manage it.

With the tail light unplugged, plug the reflector's connector straight onto the OEM socket and check operation with the running lights on and the brake pedal pressed. This confirms the units function and shows you how bright they are before you commit to a permanent splice.

Peel back the factory harness tape to free enough length, then cut the three leads midway between that tape and the tail-light plug. The CR-Z side carries a black ground, a red power/running lead, and a green (or green/white) brake lead; the reflector side is black, red, and either yellow or white depending on the batch. The original writeup paired them black-to-black, red-to-red, green-to-yellow, but many installers hit trouble with that mapping. The reliable arrangement is black-to-black, the car's red to the light's white, and the car's green to the light's red, which amounts to swapping the red and white leads. Use butt connectors rather than T-taps, which can interfere when refitting the tail light; soldered joints with heat-shrink or aircraft splices are even better. Sleeve the thin light leads in 3/8" tubing for abrasion protection.

To avoid cutting into both tail lights, run a lead across from one reflector to the other and splice only a single side into the OEM circuit. Installing a serviceable disconnect at the diffuser, such as a Deutsch connector or a set of male/female plugs, is worthwhile since these LEDs are known to fail over time and a plug lets you replace a unit later without re-splicing.

Factory fitment is loose, so fasten each unit rather than relying on adhesive alone. The reflectors have screw holes on their inner face; drive a small screw, a #8 x 1/2" sheet-metal screw works well, through the diffuser's pre-drilled holes from behind, which can be done with the diffuser still on the car. Double-sided tape is a weaker fallback where no screw will reach.

Refit the diffuser and tail light. With everything reconnected, confirm the reflectors glow with the running lights, brighten on the brake pedal, and blink with the unlock chirp if your car does that. Then check that the head-unit backlight and daytime running lights do not dim under braking, that cruise control still engages, and that no VSA or system-check warning appears. Any of those symptoms points to a wiring error, usually resolved by swapping the red and white leads.