Blind Spot Monitoring Retrofit Help

[2018gti]

Just to offer another way, which is how I did it: either cut the blind spot wire or de-pin one end of it, and tape it to the existing harness. Then spray some silicone lube into the tunnel where the wires go in the mirror, and just slide it through. Then re-pin or solder it back together. Voila!

 

[Nuje]

...tape it to the existing harness...

I don't quite grok this; if it's taped to the existing harness, how to you force two super-skinny-gauge wires through such a congested (non)opening?

 

[2018gti]

It is tight for sure - by taping I mean like fishing the wire through. You’d spray silicone inside the tunnel, pull the harness gently from the top side so it slides from bottom to top maybe 4-5 inches, then tape the blind spot wires to the main harness and pull it back down so the small wires end up out the bottom of the mirror. Hopefully that makes sense lol.

 

[Nuje]

Ahhhh - I got it now. Actually move the OEM wiring harness up/down through it's "tunnel" to help the fishing expedition. Will give that a try for sure.

 

[2018gti]

fishing expedition

Precisely

 

[Nuje]

Ok - that worked shockingly well! Thanks for the tip. One mirror down, one to go. I'll take some photos while I'm doing the second mirror to help illustrate your method.

The hindrance for me now, though: How do you get to the back of the 27-pin harness (TTVL and TTVR in the wiring diagrams) to actually connect those mirror wires to the wires run from the control modules? Disconnecting at the door hinge was easy enough to get the car-side of the wires into the harness, but I'm staring at the door side and can't even figure out how that comes off door, let alone how to get wires to the backside of it? Drill out the rivets and remove the speaker...?

 

[IWMTom]

Ok - that worked shockingly well! Thanks for the tip. One mirror down, one to go. I'll take some photos while I'm doing the second mirror to help illustrate your method.

The hindrance for me now, though: How do you get to the back of the 27-pin harness (TTVL and TTVR in the wiring diagrams) to actually connect those mirror wires to the wires run from the control modules? Disconnecting at the door hinge was easy enough to get the car-side of the wires into the harness, but I'm staring at the door side and can't even figure out how that comes off door, let alone how to get wires to the backside of it? Drill out the rivets and remove the speaker...?

You don't need to remove the speaker. Once you've detached the door side and chassis side, run a snake from the mirror to the door side, then just pin the wires in.

 

[Fraysa]

Any chance you guys can take photos of the process? If you found an easy method to fish the wires, I'd definitely try this retrofit.

 

[2018gti]

Any chance you guys can take photos of the process? If you found an easy method to fish the wires, I'd definitely try this retrofit.

I’m sure Nuje will have better pictures but here’s a couple from when I did it a while ago. I didn’t de-pin the wires, I actually cut them which is a bit of a pain to solder back together. If I did it again I’d try de-pinning first. The wires were extracted from my stock mirrors.

it wasn’t what I would call “easy” haha but it works.

The 2nd and 3rd pic is of it finished. You can see in the 2nd the main harness go down into that tunnel kind of thing - what I did was pull upwards on the harness several inches, then tape the two little pins there and pull it back down. I suggest silicone or wd-40 in the tunnel since if it’s dry the harness gets scuffed and can start to rip.

 

[Nuje]

Once you've detached the door side and chassis side, run...

Chassis side: easy to detach - little tab at top presses down to release.
Detaching that connector on the door side, though....? I'm totally at a loss.

Took me a while (and some help) to figure out how to get apart the connector that plugs into the chassis side to actually get the wires from the door plugged into the back of this connector: slide wiring part in the direction indicated and it pops out easily.

I'll get some more photos when I do the second mirror (today or tomorrow).

 

[Nuje]

Ok - some photos of how I ran the wires out of the mirror into the door.
Starting point, with the cap and glass off:

Not shown, but un-do the plug on the inner door (door card pulled off) so that black wire harness has room to come out of the door. Don't have to feed the wire plug at the end into the door - I had enough length just leaving the wire connector at the opening where it goes into the door.

Pull mirror out and cut the little zip tie:

Spray some silicone spray or similar down the little channel (I used PTFE spray) and start working that black cable back and forth so you can pull it out from the door.

Take the two wires (yellow and brown at LH door) and tape them to the black wire bunch.

Grab the wire at the opposite end of the mirror and yank the bunch through. Might take some twisting of the wires and some back and forth as there really isn't much room, but it'll go through.

Note the somewhat atypical orientation of the BSM plug on the back of the mirror glass.

I popped off the black plastic frame of the mirror to run the wire out from the bottom, which looked like the "factory" pathway (and was same as where the mirror glass heater wires run). Three T10 screws hold it on.

Be sure to clip in the bottom of that frame as you're re-installing it.

Mirror heat wires re-connected and BSM wire run in provided holders on the bottom:

That's about it. Push the glass back onto the holder. Screw down the mirror back into the door.

Then try to figure out (and report back here, please) how you get those mirror wires you just ran into the connector on the door side of the hinge.

 

[Nuje]

You don't need to remove the speaker. Once you've detached the door side and chassis side, run a snake from the mirror to the door side, then just pin the wires in.

I've got the door off the hinges (E8 Torx and M10 triple-square) so I can get a straight line through that rubber accordion-like wire channel, but I still can't find a way to get from the harness/connector in the foreground into the door cavity, let alone coming at it blindly from the other direction.

 

[xabhax]

I've got the door off the hinges (E8 Torx and M10 triple-square) so I can get a straight line through that rubber accordion-like wire channel, but I still can't find a way to get from the harness/connector in the foreground into the door cavity, let alone coming at it blindly from the other direction.
View attachment 222474

Damn you took the door off, thats dedication right there.

 

[Nuje]

Friend who's a tech at VW told me it's dead-simple (and it is). The two E8 Torx basically just keep the hinges from popping out - no adjusting there. And then the M10 triple-square holds the arm that provides the opening detents - again, it doesn't adjust.

Remove M10, back out the E8 screws, detach wiring harness (already done), lift - that's literally all there is to it. Heavy and somewhat unwieldy for one person, but I managed fairly easily. Two people would do this dead-simple. And putting it back on is equally simple - and like I said, no adjusting necessary. It just fits.

 

[xabhax]

Friend who's a tech at VW told me it's dead-simple (and it is). The two E8 Torx basically just keep the hinges from popping out - no adjusting there. And then the M10 triple-square holds the arm that provides the opening detents - again, it doesn't adjust.

Remove M10, back out the E8 screws, detach wiring harness (already done), lift - that's literally all there is to it. Heavy and somewhat unwieldy for one person, but I managed fairly easily. Two people would do this dead-simple. And putting it back on is equally simple - and like I said, no adjusting necessary. It just fits.

Damn, makes me feel like an idiot for struggling with the connectors and wiring with the door on. Will keep this in mind next time