Can Bus wiring driver's door

[mtroxel]

I'll buy a steak dinner* for anyone who knows this one. I keep getting CAN communication errors between the Convenience Module and the driver's door module. Usually it's a single wire error. Tracked down the orange/brown stripe to the low CAN, and I have continuity to the plug in the kick panel. But this diagram from Bentley is not right. I see the orange/green stripe out of the door module, but it is in no plug behind the driver's side kick plate. And it is not in plug T20 pin 20, that plug only has 17 pins. Does it just go straight to the inst cluster through the harness?

Note: A146 in this drawing is the high CAN.



* You must pay your own expenses to Minneapolis to collect.

[Let it snow]

A4 B6 lurker here. I recently had a similar problem. A146, A147 and B207 all start at the Comfort module then tie into each door at the door jamb plug. The T20 is referring to the door jamb connection. My red/grey wire (B207) was broke at the drivers door. I had no codes but the window switches did not work except for the drivers remote switches. Did you check you door connection?

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[mtroxel]

I feel pretty stupid. Took the other side of that boot off but thought T20 was behind the kick panel like all the others. You're right, here's mine. I see my CAN wire, and the problem.



I don't want to break that plug, and it's not obvious to me how to unlatch that and pull it out. I assume that purple thing is some sort of plug latch?

[Let it snow]

I can not remember for sure. Either you push the purple thing forwards to the front of the car or if you pull it back towards the rear of the car. You will know, it moves easily. With the purple thing disengaged the plug will wiggle/pull out towards the door. Brace yourself a new harness is not cheap. Good luck.



I will send you my address LOL.

[mtroxel]

Either you push the purple thing forwards to the front of the car or if you pull it back towards the rear of the car.

I pushed it to the front, and wrestled the plug out of there. Didn't learn a thing. But just the CAN wire is broken now, and a few others have a pretty good crease in them.

Brace yourself a new harness is not cheap. Good luck.

Yea looks like everyone online is about $220. I see a few from Moscow for close to $100, don't think I'll be doing that. For anyone searching, on a B7 its part #8E1971029AD. Looks like a tough splice job. And at this point, I don't think I'd do it unless I spliced every wire in there.

I will send you my address LOL.

I really appreciate the help. But the terms of the steak offer are very clear. The steak is in Minneapolis. Expedia can help you. Its 78˚ and gorgeous here!

[mtroxel]

I might take one for the team give this a shot. $63.00

VEMO V10-83-0066

[Van Black]

I'm not 100% splicing CAN wires is a good solution. It will change the wire resistance which might lead to faulty comms between modules; don't have any real world proof though

[Caconway2322]

I got a spare b7 door harness in Ohio $150.00 3302427368 call or text


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[Axis]

I'm not 100% splicing CAN wires is a good solution. It will change the wire resistance which might lead to faulty comms between modules; don't have any real world proof though

My canbus high/low have been tapped with positaps without incidence for 2-3 years now.

[Let it snow]

Great find mtroxel. I did not know about this. Looks like a great option. Thank you.

https://www.ecstuning.com/Search/Sit...066/ES2902986/

[Okedokey]

The resistance difference between a spliced and original will be negligible.

I would just repair it.

[mtroxel]

I don't expect this to be a long term fix. But I spliced a new piece of 18 gauge wire in there. I tend to solder a lot, you get a low resistance mend that is very sound mechanically. However, you also get a stiff section of wire and I would guess all the flexing will be at the end of that solder joint which means it's even weaker than the original.

If you pull the woofer out of the door and raise the glass, you can work the whole plug/flex assembly out through that speaker hole and do your repair. I pulled my CAN wire back through the plug.



Then I pushed my new 18 gauge wire through and twisted it together with the CAN wire. Soldered it up, then wrapped in black duct tape (cause black is stronger, just look it up).*



Pretty much did the same on the other end and crammed it all back through that hole in the door.




* Yes, it's a joke.

[Van Black]

The resistance difference between a spliced and original will be negligible.

I would just repair it.

Like I said, I've never tried it, in my line of work it's cheaper to replace the harness that to risk getting CAN errors

[mtroxel]

Like I said, I've never tried it, in my line of work it's cheaper to replace the harness that to risk getting CAN errors

I understand that. When I'm charging for me time I do things much differently. Right now I have no CAN errors. If that changes soon, I'll go back in and do a better fix, maybe the Vemo repair harness above.