Pete S

Was wondering if anyone knew if there is an easy access point to the third brake light wires. I have installed the Kahtec smart stop on all my cars and want to add it to the R also. I have found a thread explaining how to remove the lens but I don't know if there is enough space back in there to install the small Kahtec module, plus it looks to be quite tedious as I can see myself losing multiple screws into the rear hatch. Anyone know if the wire is located in one of the rear wheel wells that have access through those cubbies near the tail lights? Or possibly what color coded wires I should be looking for? Thanks in advance for any help.

efzauner

I believe the wire for the 3rd brake lite is on the right side, behind the panel, part of the right rear light harness. I found this looking for a good 12v parking light source for a trailer hitch and found that the license place light does the trick (the main rear parking lights are normally lower voltage until you brake, useless for trailer lighting)
So probably there, you can test with a voltmeter. But what is this kahtec thing? It may interfere with the system that checks for burnt out bulbs as the car electronics checks for current draw. If the kahtec system draws insufficient current it will cause a *burn light* warning.

Pete S

efzauner my 96 SL also has bulb warning light and it has had no issues with the kahtec and a friend that has a newer 09 SL with the same thing has no issues so I think it will work in the R also with no negative effects. Basically it is a small module that you splice into whatever wire takes power to the third brake light. They have various versions but I usually get the one that blinks the 3rd brake light 6 times quickly (maybe in a span of 2 seconds or so) and then goes solid until you let go of the brakes and do it all over again.

With as many people texting/surfing the net/playing games or talking on their cell phones this helps to get their attention. I really like it and have ordered one for the R, now just a matter of figuring out what color wire supplies power to the third brake light when you hit the brakes.

The website is: www.kahtec.com btw I have no affiliation with this company I simply buy their products. This is the 4th I buy for myself and have even gifted one to my brother. The module is tiny maybe
1/4"x1"x2".

Here is a link to what it looks like in action. This was on my SL. It's the 8 second delay version I have since switched to the standard version but gives you an idea what it does and how it hopefully gets the attention of drivers behind you.

AsianR350

i have this light installed on my motorcycle and it works great.

Pete S

Spent some time to figure out which would be the 3rd brake light wire with no luck. Might have to buy a one day subscription to Startek to download a wiring diagram.

AsianR350

If you do not mind to remove the hatch back panel, you should be able to access to the third brake light and splice the wire from there.
Note: I have removed the rear panel before to install the back up camera.

Pete S

AsianR350 I noticed that along the top it looks there is a center piece that may just pull off but I hate just pulling away at stuff worried that I may break something and if I do get it off I have no idea if it will reveal anything. Pain in the butt this one.

AsianR350

I am not sure what you are taking about. When remove the rear panel, you might break the fasteners and need to replace the plastic fasteners (dealer sells a pack of 10 or 12) and I also used a panel /door removal tool to remove the fasteners .If you need a instruction how to remove the rear panel , I might able to post here for you.

Found the photos.

efzauner

Pete... remove the brake light and see what colour wires lead to it... find those same colour wires in the harness by the left or right rear brake lights... test with multimeter.

Pete S

Efzauner I think that is my last option but looks to be a royal pain in the butt to get it off. They rally didn't leave much room in the liftgate to get it off easily. I have torch style screwdrivers but don't think there is enough room for them to fit and my torx socket set probably won't fit through the holes. Can't even imagine how hard it will be to get those screws back in when you are basically trying to do it blind. This mod is turning out to be more work than it's worth.

Pete S

Thanks everyone for the help. After looking at the pictures AsianR350 posted it looked like I could simply pull off that one piece of trim along the center top of the hatch and once that was off I could see the wifing going to the 3rd brake light. Spliced into it there, taped up all the connections and the little module I two way sticky taped to the trim piece and popped it back in. Thanks for all the help, working perfectly and no bulb warnings.

AsianR350

I am glad that you had the third brake light done.
Any photos of your installation?
I would love to do that on my R too. Where did you get your part and how much?

Thanks Pete.

Pete S

AsianR350 if you want I can pull the panel off and take some pictures as well as make a quick YouTube video. I ordered the part from Kahtec.com I order the standard version which blinks the 3rd brake light every time you hit the brake. I live in an area where there are alot of stop signs so decided to go with this version. If you live in a more rural area the Delay version might be a better option as there is a 8 second delay i.e. if you hit the brakes then let go and press them again within 8 seconds the third brake light will not blink again, there has to be more than 8 seconds between braking for the system to blink the 3rd brake light again.

If you want to see the install let me know I will take pictures, didn't seem to be too much interest so I didn't bother to take pictures of the install, but would be ore than happy to help.

AsianR350

I would love to see how you did it. But if you do not mind to take the photos of your third brake light 's installation, I would appreciate your times.

Thanks Pete.

Pete S

I will I won't take pictures of the actual connections as they are all wrapped in tape but will do a write up along with pictures of it already installed. I'll see if I get to that this weekend.Today I just finished installing the Rosen rear entertainment. Mounted the screens, fished the wires down through the head rest holes out the bottom. Hopefully tomorrow my buddy who installs this type of stuff will wire up all the necessary connections but we still have to fish two cables for one seat to the other depending on where he will mount the control box/FM Modulator. Looks great though.

Pete S

I had a few requests on how I installed this so today I took everything apart and re did the entire install for the benefit of anyone looking to install this item.

Items/Tools needed:
Kahtec Smart Blink Module available at kahtec.com I buy the standard version.
Trim removal tool
Wire cutters
Wire stripper
Heat Shrink or Electrical tape. I used both as I like using heat shrink when possible.
Install should not take any longer than 30 minutes.

To start you want to pop off the center trim along the top of the hatch. (picture 1) It is held in place by four clips and has an alignment pin in the middle.

Next insert a pry tool to pop off the first clip, (picture 2) once you get the first one off use your fingers along the top edge to pull the rest of them off. You want to pull towards yourself not up or down.

Picture 3 has arrows pointing at the 4 clips that hold the trim piece in place and the Kahtec module mounted to the trim piece using a piece of 2 way sticky tape.

Picture 4 is the location of the wires you will need to tap into. There is some extra wire that goes through the hole and to the third brake light. Pull some of it out to give yourself some room to work. Peel away some of the fabric tape to expose the 2 wires, blue/black and brown.

Pete S

For some reason it only allows 4 photos to be uploaded, if a moderator ants to merge the posts together feel free otherwise I will continue below.

You are going to want to cut the blue/black wire (12V to 3rd brake light) and strip both ends. On the brown wire (Ground to 3rd brake light) just peel back some of the insulation so that you can wrap the black wire coming from the Kahtec module no need to actually cut the brown wire wire. (Picture 1)

Next you will want to connect the red wire coming from the Kahtec to the blue/black that comes up the hatch, this is the 12V lead. Next connect the blue wire from the Kahtec to the blue/black that leads to the 3rd brake light and wrap the black wire from the Kahtec around the exposed part of the brown wire. I used heat shrink for the 2 wires I cut and electrical tape on the ground that I only peeled some of the insulation from. As I mentioned I like using heat shrink when possible but using just electrical tape won't cause any issues as long as you wrap it correctly. (picture 2)

Picture three is simply all the connections completed. All that is left now is push some of the wire you pulled from the hole back in there and simply align and push the clips back in of the trim piece and you are done.

Hope this helps anyone looking to tackle this project.

Here is a link to a YouTube video so you can see how it works.

AsianR350

This a good DIY. Thanks for your great contribution to the forum.
So the red(+) and blue(-) wires from the module are connected in series to the blue/black wire of the third brake light respectively, right?

Pete S

Correct. The red goes to the side that brings 12V when you hit the brake and then the blue on other end. As you said you are putting the module in series, but I do think the red need to receive the power and the blue then puts out the 12v.

AsianR350

I just ordered the module for $28 shipped.
The installation seems very easy. I plan to solder the two splice wires then put heat shrink over it. The third one (ground) will be covered with the electrical tape. The module will be placed with 3M heavy duty 2 sided tape to the plastic cover as yours.

Thanks again.

Pete S

Pretty much what I did minus the soldering. I just wrapped the two wired pigtail style and hear shrunk. Every way discussed works, but yours will be the best connection for sure.

AsianR350

Peter S,

Thanks for all the tips.
I finally installed the KAHTEC Blinking Smart Stop Module.
I soldered the joints for good connections.

Pete S

Nice work AsianR350. Glad to help the forum if it's just a little. I have these on all my cars now.

vanable

Quick random Q: when you guys are under there doing the wiring, can you see if the rear spoiler is removable from the tailgate door...? Or does it appear to be part of it?

AsianR350

I took a look at the rear spoiler and it is part of the rear hatch. I believe they sell the rear spoiler for R63 that might have 3M double tape to put on top of it.

Here is the photo of the roof rear spoiler.