This is how to replace your 3rd brake light with an L.E.D. replacement bulb without setting off your DSC or ABS lights.

I first started by removing the trunk's plastic grab handle by prying it off with a flat head screw driver. (it's only clipped in). Pry from the side closest to your rear window then pull toward the rear bumper to remove.

I then removed 13 plastic screw-type plastic clips holding trunk lid liner on the trunk lid
(simply unscrew and pull out)

Then I removed the clip plugged into the 3rd brake light bulb socket.

Then rotate 3rd brake light socket counter clockwise to loosen, then pull out to remove 3rd brake light socket and bulb.

I replaced my 3rd brake light bulb with some e-bay L.E.D. replacement bulbs
I got 2 for about $13.00 bulb size 7440 (note: you will only need 1 red 7440 bulb)
(1st pic)

I then got a 2 watt 150 Ohm wire wound resistor. I then Soldered 2 wires to the ends of the resistor and cut the excess off. You will want some extra wire to place the resistor where you please when connected on the trunk lid. I had this one (2nd pic) but a hardware store that sells electrical resistors should have one. (Radio Shack)

 

I then cut a slit in the plastic wire sheath on the RX-8's 3rd brake light wire plug to expose the 2 wires inside. I then cut a circle in the wire coating on the 2 wires for the 3rd brake light and soldered my resistor in parallel ( 1 end of my resistor wire to 1 wire and the other end of my resistor to the other wire in the sheath).

Then be sure to wrap all soldered connections in electrical tape to protect the connections from connecting to each other or other metal.
(1st pic)

I then zip-tied the resistor to one side of the 3rd brake light housing and placed it in a nook of the 3rd brake light housing so as not to affect the fitment of the trunk lid liner.
(2nd pic)

Then I replaced the trunk lid liner, replaced the 13 screw type clips and snapped the trunk lid handle back in and have not had any ABS or DSC lights since my install.

NOTE: I tested my resistor to make sure it would not set the DSC or ABS light by removing the 3rd brake light bulb out of the socket and connecting the resistor leads directly into the socket and holding the brake. The resistor I used is probably old and the one you find to use may not look exactly like it. Resistors tend to get hot when in use, be sure to have someone hold the brake while you hold the resistor to see how hot the resistor you use will get. The resistor does not have to be placed where I put mine. I take no responsibility for your modifying of your own car, this is simply what I chose to do to my own.

 

Does this have to be wire wound or can it be metal filmed?

 

Meh, for $30.00 you can get a whole LED 3rd brake light and not have to mess with a resistor.

 

You don't need a resistor if you only replace the third brake light with LED... only if all three brake lights are LED.
But what's the point to do just the third bulb?

And even with the LED third brake light mentioned above you'll usually need a resistor if the other two bulbs are also LED. If you are lucky, you may not need it as some people found but having all LED in the back most likely will trigger the DSC / ABS light.

Oh, and it will cost about $38 or so to buy the all LED third brake light (extremely inflated shipping cost included). At least that's the going price on eBay. Or is there another, cheaper source?

 

10 ohm 10 Watt wirewound resistor from Radio Shack. Part# 271-132 (for a pair)

Mounted using some bent galvanized pipe strap, held in place by the stock plastic fastener for the brake light wires.

Two such resistors in parallel will also work as turn signal load resistors. You'd need these on all four corners. But then it's probably easier and cleaner to use the intended load equalizers that v-leds and others are selling.

 

Cleaned and adjusted internals of brake switch and now works great with no resistors. Brake switch has two switches built in and they are opposites one is on the other is off. Probably sends signal to ecu. I have all three brake lights in led and have been fighting this issue for 3-4 years. Resistor mod never completely fixed my issue.

 

my tail lights are led and i have resistors on them from rotaryfx, if i get the 3rd brake light led thing off ebay, will i need another resistor?

 

You don't need resistors at all to run LED in any brake light. If you get the ABS/TCS lights on check your brake switch. See the post before yours on how I fixed the issue.

 

So if I dont put the resistor will it triger just the lights of DSC/ ABS or will they actually not work?

 

What exactly do you mean when you say cleaned and adjusted internals? Could you expand a bit? Maybe a small DIY or something. By all the different posts of different resistors and what not I've tried 2 different resistors now and it hasn't fixed my problem.