05-’06 Acura RSX taillight rewiring guide

When Acura unveiled the facelift for the 2005 RSX, many gave the minor design changes two thumbs up and a nod of approval. However, many became disappointed to learn that only 1 lens on the taillight lights up at night. This article guides you with great details on how to rewire the taillights so that both the lens on each taillight assembly lights up with your parking lights – akin to the ‘02-’04 models.

Please note that this article was originally written in 2005.

I finally had the time to sit down and work on this highly requested mod (disregarding the months of procrastination). With all the parts and tool on hand, it took me 23 minutes to complete, not too shabby. The purpose of this mod is to rewire your 2005 or 2006 Acura RSX taillights so that both inner lens and outer lens light up at night. You will retain your blinker signal as well. Basically, you’re swapping out the socket & plug from your taillight signal lens with a 3-pin socket/plug, and tapping the power wire from the neighboring outter lens.

The parts you need are:

2x 3-pin plugs, part #: 04321-S2A-308 (you need to buy only ONE; part #:04321-S2A-308 is sold as a bag of 5 plugs)

2x dual filament wedge bulb, T20 W21/5W; part #: 34906-S30-003

2x 3-pin sockets, part #: 33515-S2A-003

2x T-Taps, 22awg
2x male quick disconnects, 22awg
2x butt-connectors, 22awg
1x roll of wire, 22awg
1x hacksaw

1 wire stripper/cutter

1x salvaged wire plug from any Honda/Acura with at least two pigtails (wires with terminal)

You should be able to find most of the electrical parts at your local RadioShack or AutoZone. I found most of mine in my tool shack . A good place to order bulk of electrical component is Mouser, Inc.. Simply a great company, no doubt. For the sockets, wedge bulbs and plugs, you can order it from Delray Acura. Just punch in the provided part numbers and add to cart. So far, I’ve found that Delray offered the most economical price for these parts.

And finally, you need two pigtails to complete the mod. I just salvaged mine from a 4-pin plug with wires from a Civic power window wire harness at a local junkyard. You can order these pigtails from Acura too, but I don’t think it’s worth the $9.00+ per bag of 10 pigtails they are charging (after all, you don’t need 10 pigtails).

I. Working with the taillight plugs and sockets

The first thing you want to do is remove two pigtails from the salvaged plug. To do this, take a small screw driver or probe and pop out the wire retainer on the salvaged plug as follows:

With the retainer removed, take your mini screwdriver or probe and dislodge the wires from its housing. If you have a terminal release tool, even better. This is a bit tricky so take your time not to damage the wire terminal or plug. If you damage the plug in the process, you’ll probably have to saw it in half to remove the pigtail:

This is what a pigtail looks like:

Three other pigtails:

If your pigtail is long enough, i.e. 8.0″ or longer, you can skip the step below and jump right onto attaching the male quick-disconnect at opposite end of the pigtail.

Take the wire stripper and strip the end of the pigtail as shown above. You will connect the end of the pigtail to another strip of wire later.

Cut an 8.0″ strip of wire from your roll of 22 AWG wire and strip both the ends:

With the ends stripped, connect the pigtail to the newly stripped wire with a butt-connector. Simply crimp the butt connector at the middle, securing both wires together:

Or if you want an even more secure connection, you can alternatively solder the stripped ends together and then place a heat-shrinking tube over the soldered area and heat it up to shrink the tubing.

With the 8.0″ wire connected to the pigtail, crimp a male quick disconnect (measuring 22 AWG) at the other end of the 8.0″ wire:

The completed wire set should look something like this:

(The above pic shows a wire set completed with the solder/heat-shrink tube method.)

Next, take the 3-pin socket and look at it from the top where the wedge bulb is inserted. Saw off the tab as depicted:

The reason you need to saw off these two tabs is because they will obstruct the socket from plugging into the taillight compartments securely. At this point, you may optionally use a file and file down the edges from the sawed-off point.

Next, remove the taillight access panel and remove the turn signal socket. Remove the socket / bulb from its plug. The plug should have two wires, GRN/YEL (right side) or GRN/RED (left side) along with a BLK ground wire. Pop off the retainer as you did with the salvaged plug using a probe or a small screwdriver:

Again, using the probe or small screw driver, maneuver both wires out of its retainer:

Next, remove your brake light bulb (outter lens), then remove the socket from its plug and examine the three wires. The black wire is the ground wire, the red/yellow wire is the parking light wire, and the white/black wire is the brake wire:

Using your wirestripper, strip a part of the RED/YEL wire as shown. Use the 22 AWG stripper and strip the wire carefully, you just need to expose the copper wires and that’s it. Be careful NOT to cut the wire:

You can strip any RED/YEL wire from the taillight assembly as they all perform the same function. It is a generally a better idea to strip the RED/YEL wire from your brake lights (outer lens).

Next, take a T-Tap and place it over the stripped portion of the red/yel wire, then snap it shut (you may need to snap it with a pair of plier). Make sure you hear a click to ensure that it is properly secured onto the wire:

With the T-Tap in place, take your wire/pigtail combo and plug the male quick-disconnect into the T-Tap. Cut a piece of wire insulation tube/loom to approximately the same length as the wire/pigtail combo and cover the wire with it:

With all that completed, take the 3-pin plug you’ve ordered and pop up the retainer. Insert the two wires you’ve removed earlier and the pigtail into it: signal, parking light, ground (GRN/RED, RED/YEL, BLK).

Make sure the wires are inserted in the order as pictured below:

One thing you should keep in mind is that the middle wire is always the wire/pigtail wire that’s being tapped to the parking light wire.

Once the wires have been inserted, snap the retainer of the 3-pin plug back into place to secure the wire terminals, then plug the 3-pin plug into the 3-pin socket (with the two sawed off tabs), plug in the wedge bulb and then plug the connector back into your taillight assembly:

Test out your newly rewired taillights by turning on your parking lights. Both circular lens should light up. Flip on the left turn signal with the parking lights on, your left turn signal lens should light up AND blink at the same time. Repeat with the right lens. Next, turn on your emergency blinkers and see if it works without strange flickers.


If you passed all the test, you are good to go. If the blinker either blink to fast, doesn’t blink or flickers, then you probably have the wire mixed up when you inserted them into the 3-pin connector. Remove the retainer and start over.

Don’t forget to store the original bulb/socket and plug in a safe place in case you want to revert back to stock:

Basically, repeat the same process for the opposite taillight. The whole mod took me no more than 30 minutes, including clean up.

Be prepared to blow your turn signal fuse if you accidentally cross the ground and signal/parking light wires while inserting them into the plug. So.. make sure your light switch is off and you have a few 10amp Mini fuses handy just in case!

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