Passat B6 Rain sensor retrofit

Parts that you will need

 YOU MUST HAVE HIGHLINE CECM, OR ONE THAT SUPPORTS RAIN SENSOR FEATURE!!

1. 3c0 857 304 TRIM (Headliner Connector) add y20 for pearl grey, 7g8 for beige

2. 3c0 857 511 d MIRROR (auto dimming) add sma for pearl grey, tlx for beige, tly for latte

3. 3c0 857 593 a 9b9 WIRING COVER black

4. 3c0 858 547 9b9 LEFT MIRROR COVER black

5. 3c0 858 548 9b9 RIGHT MIRROR COVER black

Rain sensor number: 1k0 955 559 with suffix AF, AH, R, M. 

*** Notice***

It is likely that you will have to replace your windshield, because it can crack while you are trying to remove old glue. 

if you have no spare windshield, or you want to take a risk with your old windshield, then you have to follow steps bellow: 

Remove the original mirror mount by heating the mount with a lighter and twisting it off. Do not push or pull it, just twist it with medium force using a wrench. Any more and it will crack the glass. Use a razor and scrape and then polish all the ceramic backing paint off. Then use 1000 grit wet sandpaper to gently remove the ceramic paint. If you don't remove that dot you'll have to mount the mirror too low and there will be exposed wires. digitalextremes said it took him at least an hour to remove the paint. Then try to polish it as smooth as possible so that the glass has no noticeable scratches.

pic3

You must remove all of this old glue. So keep unitl you have result, as shown on pic3.

Use 3m fast cure urethane and primer. The urethane glass glue is 8690 and the primer is 08682. The key to making this look OEM is the 3m 08682 primer. This stuff is designed to black out in front of urethanes to protect them from the sun. Just mark a center line on the outside of the windshield with a sharpie (remove with solvent) and use the shorter of the two cable covers attached to the mount to determine the spacing to the headliner. Mark, mask, and paint. The glue is very viscous and you can pretty much just press the mount on and it will hold it until dry. 

Clean the windshield with cleaner VW# d 009 401 04  and let dry for at least 10 minutes. Apply primer VW# d 009 200 01  and let dry for at least 10 minutes and not more than 1 hour. Use 800-1200 grit sandpaper to roughen the mount until water won't bead up or run off it. Use the cleaner on the mount.

Apply the new mount (VW# 1k0-845-543) to the windshield. The slide tracks for the new mirror must face down (be on the lower half, visible in the pictures throughout this page). The new auto dimming mirror just slides up to install, down to remove. Apply a 2.5mm bead of VW's 2 part polyurethane glue (shown earlier in parts) to the mount and tape it in place. After an hour, you can remove the tape and scrape/wipe any excess off. The service manual says that you can mount the new mirror after 2.5 hours. 

If you won't use your old windshield:

Remove the overhead console. First gently pry the sunglasses holder out. There are some clips at the top holding it. The middle panel will just pop out. Remove the 2x T20 screws under it.

Next thing is to remove A pillar.



Wires will go through the a pillar but be carefull, because of airbag.



Wiring instructions for auto dimming mirror and rain light sensor

The easy way to do the wiring is to buy a premade harness on ebay. One person complained that the plug ends were at equal lengths and because the sensor and mirror are staggered, he had to unwrap and re-wrap it for fitment. Since it's only a few wires, I chose to buy some plugs, VW repair wires (part numbers are noted above) and then splice 18 or 19 gauge extension wires onto the repair wire ends to make my own harness.

Run the wiring from the rain sensor and mirror behind the headliner, down the a-pillar, tape it to the existing wiring, and down to the CECM (central electric control module) for the fusebox and ground.

Remove the 2x T20 screws holding the kick panel under the relay box. Then unplug the footwell light and separate the OBD2 port from the panel. Push the red lever on the CECM to the side to unlock the plugs. The plugs are labeled. Press the release clip on plug B and F and pull them out. You can remove a few others for access. The wiring is pretty short and the plugs are different so I don't think you could mix them up. Plug B is outlined below. You can see the red lever to the right of the relay box.

The plugs also have numbered pins. Solder in a splice on Plug F, Pin 3 (violet/blue wire as noted above, this wire also goes to the windshield wiper module) and run that wire up the A-pillar and headliner to the repair wire on pin 3 of the rain-light sensor. Cut the wiring to fit and solder them together. Splicing means that you tap into the connection and add your own wire. I chose to strip a little bit of insulation off that wire and soldered in the tap wire at that spot. Cover with electrical tape. 
Repeat for Plug B, Pin 1 (black/blue wire). This is for the backup light. It goes to pin 3 on the mirror. 

Install 2 new circuits for the rain sensor and mirror at the fusebox. See the wiring diagram above.  Repair wire VW# 000 979 225 should work but I'm not sure of the correct part number for wiring these two circuits. 

Cut the repair wire in half. Insert the terminal ends in the indicated slots. I think the mirror fuse (#7) could go on any slot on that bus. #11 should be acceptable and easier to install since it's on the near side of the fusebox, just make a note on the fusebox cover if you do that. It gets 12V when the engine is running only. I believe the bus for the RLS fuse always has 12V.


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