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No definitive answer and it isn't really a 'reset' deliberately intended by V.W. What you hope is all voltage charge sitting on many capacitors inside all the modules will self discharge themselves through variable leakage leaving any memory with < 0.7V remaining on supply rails.

What V.W should have done is put a bleed resistor on memory voltage supply rails to discharge any residual voltage after a time they probably thought would be sufficient for a battery swap. But actually it is quite difficult to discharge very low voltages to near zero. You can use resistors first then short circuits, but capacitors have a strange behaviour of dropping their voltage initially then it can rise a small amount after a short is removed. Each module is a different design. You may be lucky after an hour or two, or you leave the car without power for 24 hours. I have a door module I removed because I thought it was 'bad', but since it's been sitting on a shelf it is now good!
 

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I guess you can't reach in and disconnect the big white plug? It's big and white and may need prising out with a flathead screwdriver on both sides.

Splicing the factory wiring loom seems like a bit of an extreme measure. One of my most important rules when working on the Eos is "thou shalt not splice the factory wiring loom, except as instructed by a VW Technical Service Bulletin".
 

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thou shalt not splice the factory wiring loom, except as instructed by a VW Technical Service Bulletin".
Why? V.W connectors are usually sized for one cable diameter entry. Sometimes it's possible to remove a pin and solder a second wire to the pin, but not always when the connector rear entry has a silicone seal. V.W use lots of hidden hard to find wire splices (taps) throughout their looms. They don't solder a splice or tap, but use an open brass crimp and tape over it with cloth tape to get wet. I would argue that soldering and heatshrink is superior to how V.W manufactured their wiring loom?

I don't do lot of splicing but when I do solder and sleeve, I never use Scotchloks and always keep a diagram of wiring mods and the wire colors I've used. Many aftermarket addons come with nasty Scotchloks for easy install, but V.W loom wires are so thin they easily cut the wire. Being open, water and moisture easily gets into them.

It's still pointless shorting out module connectors if they use a reverse voltage blocking diode internally. I have spliced semiconductor spike protection devices to my rear door single line LINbus wires. That's not in a Technical Bulletin and something they should have put inside the control modules. I haven't had a rear door module go sick since.
 

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Why? V.W connectors are usually sized for one cable diameter entry. Sometimes it's possible to remove a pin and solder a second wire to the pin, but not always when the connector rear entry has a silicone seal. V.W use lots of hidden hard to find wire splices (taps) throughout their looms. They don't solder a splice or tap, but use an open brass crimp and tape over it with cloth tape to get wet. I would argue that soldering and heatshrink is superior to how V.W manufactured their wiring loom?

I don't do lot of splicing but when I do solder and sleeve, I never use Scotchloks and always keep a diagram of wiring mods and the wire colors I've used. Many aftermarket addons come with nasty Scotchloks for easy install, but V.W loom wires are so thin they easily cut the wire. Being open, water and moisture easily gets into them.
I’m probably being overly cautious, but I don’t like doing things in a way that can’t be undone later - and often there’s not much slack on the wires so it makes it quite a tight job. I’m far from the world’s best when it comes to soldering, so I prefer to do that away from the car - creating a plug-and-play harness for any required mods is easier for me.

I have also seen other people’s poor quality DIY wiring and I really don’t want to be one of those people! Just today I was tidying up a wiring nightmare of someone else’s creation in another car. Electrical tape everywhere!
 

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O.K. If you do more solder and sleeve you get to like it. I always try to minimise the number of connectors and connections. In damp cars they can be more unreliable than a single solder splice with heatshrink sleeve, which also makes the joint watertight, I then wrap with cloth loom tape. In the old days we were taught to make a good mechanical joint first then solder it. With harder aluminium based solders I find solder lap joints are plenty strong. V.W use minimal copper in their wiring which is where i would prefer to solder. I never use electrical tape, it just peels open in hot weather. Sometimes there's a need to wrap over a joint when you can't sleeve it. I have some self amalgamating tape for that.
 

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I do like solder and sleeve - it's just much easier when you're doing it on the bench! In the car it's a lot harder even to get the heatshrink sleeve far enough away. I do need to practise though ;)
 

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I'm very careful, but I use a piezo gas lighter now for shrinking in tight places.:) The hard part is needing 3 hands to hold 2 ends together whilst making a solder lap joint. I have the answer now: Cut thin 'bands' of heatshrink, push over the long shrink, flux the ends and use one thin band to temporarily hold each wire end together. The solder will wick between the 2 wire ends, cut the thin band off & slide over the long sleeve, shrink with gas flame. Also works where you have a tap formed from a bunch of wires together - put a temporary band of shrink around them, then you only need 2 hands - one to hold the bunch and a second to solder the joint. For those type of large open ended solder connections, I slide the shrink over then whilst its shrunk and hot, squeeze the end of the shrink to form a 'teat' and weatherproof seal. If I have concerns about weatherproofing a solder sleeve joint I may dab some black silicone sealer on the solder joint and wire before closing the shrink. Practice the technique. After finishing the connections with cloth tape they look just like O.E. and you don't have more connections from connectors to go wrong or introduce higher resistance ground paths.

I've replace all the nasty V.W uninsulated brass crimp taps in my roof wiring loom this way.
 

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Discussion Starter · #29 ·
I guess you can't reach in and disconnect the big white plug? It's big and white and may need prising out with a flathead screwdriver on both sides.

Splicing the factory wiring loom seems like a bit of an extreme measure. One of my most important rules when working on the Eos is "thou shalt not splice the factory wiring loom, except as instructed by a VW Technical Service Bulletin".

Going to remove said big white plug this weekend, I could move it initially with only my hands, but was paranoid about being heavy handed and denting my quarter panel with anything else like a screwdriver if I slipped. I've sourced some protection for the inside so will have a go this weekend. Going to leave it unplugged for a week or two and see if it sorts it. I have bought a secondhand module just in case, it was only £35 from my local breakers. I've done the module and regulator change on a 206cc before which looks about the same kind of hassle. But essentially the weather isn't warm enough or dry enough to do the module change as yet, especially with a front drive and no garage! Maybe buying a gazebo could be in order.

It's going for a diesel gate rollback and remap Tuesday.
 
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