HOW TO: Retrofitting tap to pass turn signals to your W123 / W124 / W126
 

Many newer cars have a nice feature where taping the turn signal lever will cause the blinkers to blink 3 times then stop. This is very handy for changing lanes on the highway. Volkswagen created a retrofit kit to add this feature to previous models. Because Mercedes and VW wire their turn signals & hazard light switch the same way adding this retrofit kit to the Mercedes is very easy.

Stuff needed:

• Turn Signal Convenience kit for the A3 Golf, VW part # 000 998 229 , ~$70
  • Includes relay (000 953 227 A), relay socket, wiring pigtail, horrible instructions, a zip tie, and some crimp connectors
  • http://www.peachparts.com/shopforum/...1&d=1270966760
• Screwdrivers to disassemble the center dash
• Wire strippers
• Soldering iron / solder
• Forceps

First let's look at the wiring diagrams.

For the Gen2 W126, others are probably similar:
http://www.peachparts.com/shopforum/...1&d=1270966437


The "Komfort Blinker" instructions:

http://www.peachparts.com/shopforum/...1&d=1270967303

So:
Continued...

It's for sure yet another feature that once you have you can't live without.

I've retrofitted my New Beetle and kind of itch to do it to the W210 wagon I passed on to stepdaughter.

This retrofit will probably work on BMWs, too, as all German cars are wired according to Bosch specifications.

See
http://www.bentleypublishers.com/bosch/Bosch-Automotive-Handbook-7th-ed-.html

http://www.bentleypublishers.com/bosch/Bosch-Auto-Electrics-Hdbk-5th-Ed.html

So here's how to install the new relay:

• Remove the ashtray, radio, and wood trim / switches / CCU from the middle dash.
• Remove the hazard switch from the wood trim. Be careful, if you push / pry too hard you can damage the veneer.
• Plug the hazard switch back into its connector. Pop the cover off of the back of the connector.
• http://www.peachparts.com/shopforum/...1&d=1271006367
• One at a time pull out the wire you need to connect to. By leaving the switch plugged in the terminals don't all fall out of the connector shell.
• Clamp the terminal in the forceps and unsolder the connection.
• Remove all the existing solder from the terminal.
• Insert both the car harness and the blink mod harness wires into the connector and re-solder. There is just enough space.
• http://www.peachparts.com/shopforum/...1&d=1271006733
• Put the terminal back in its place.
• Lather, rinse, repeat for all the remaining wires.
• Close up the connector shell. There is just enough space for all the wires.
• Now test the system. Key on and tap the turn signal lever. The add on relay should click and hold the correct blinker on for 3 blinks, then click off.
• Secure the relay in the dash. I used the zip tie included with the kit and fastened it to one of the bowden cables running under the vents.
• http://www.peachparts.com/shopforum/...1&d=1271007205
• Put the dash back together and enjoy the new feature!

I chose to solder the connections because I didn't want to modify the car's harness. You could cut the wires and use the crimp connectors included with the kit (this is what the instructions say), or use some scotch locks... but I hate hacking up the factory wiring.

-Jason

Well, I disagree. It's the one feature on our Jetta that I wish I could disable. I thought it was cool for about a month, but then I just grew tired of it flashing no less than two times if you accidentally hit the switch (holding for <=1 gets you 3, 2 gets you 2).

Two other features were annoying when I got the car, but I've fixed those: the car beeped when locking and unlocking, and to open or close the windows without the key in the ignition, you had to use the key in the door cylinder.

There are settings to disable the beep and enable the remote to open or close the windows. If there's one to control the "tap to pass" feature, I haven't found it.

There is, it's in the CCM. It's called Komfort Blinkers...

-J

Thanks, Comp. I'll look for that at the next opportunity.

Nice work Jason. Now Peter , Corey and I will be doing this! Like I needed another project

Brian

Is it really that hard to hold the stalk for 3 seconds? :confused::confused:

Looks like a LOT of work to have a blinker that blinks 3x.....


Plus, what if you are one of those people that likes to only give one or two blinks when changing lanes..... :D I am one of those people. :D Keeps things unpredictable....

Pawo, with your stable of 20+ year-old cars, I had you pegged for someone who preferred only hand signals. :egypt: It is one of those things that once you have, you get used to it - kinda like central locking. My van has them and it throws me off when I get into the real car and it has "80's style" blinkers.

Indeed, I prefer using a trafficator. :D ;)

Don't knock it till you've tried it ;) And one blink is not a sufficient indication that you are changing lanes :P

The install was actually super easy. Only took about 20 min start to finish. When I retrofit heated seats that install is going to take a lot more effort...

-J

Clever fellow. Now come up with an equivalent scheme for the wiper which will wipe it once without having to twist the wiper switch to on, then twist to off. My old Mazda had "flick wipe" where I could just hit the stalk and it would do one wipe. I miss that feature.

Rgds,
Chris W.
'95 E300D, 312K

YES. This drives me crazy about the MBs. Just about every new-ish car I've driven except for my MBs have had a "mist" feature where it wipes once and stops. For that matter, maybe a nice addition to these cars would be adjustable intermittent wipers.

The wiper business can be done easily with a PLC (Programable Logic Controller). And we had an expert PLC programmer on this forum the name escapes me. Wire the logic input of PLC to the washer button of the stalk.
If the washer button is pressed less than lets say 2 seconds then PLC activates wiper once.
Else PLC activates the washer and wiper untill the washer button is released.

There should be PLCs that work on 12 V DC and cost less than $ 100.
Somebody wanted a side business, someone thke this idea and run with it.

This could also be accomplished with a micro-controller. The low-cost Arduino would be a good application for this. You could do many other things with it too. Its fairly cheap at $30.

PLCs and ladder logic is a pain (imo) when compared to other programming languages.