Convenience Control Module Swap

[RUM4MO]

Just another point, had another mechanic and my uncle who is very good with electronics take a look at the second burned out unit. The units aren't melting due to an electrical short, they are essentially overheating because the lock was sending a lock/unlock signal to the relay over and over and over. So it's either bad wiring in the passenger door, that I have now changed, OR, as another expert auto electrician said ages ago, the door lock isn't lined up correctly with the car body and the lock isn't fully locking when auto lock kicks in and it's sending the message over and over again to lock and unlock until it burns out. I think I have finally cracked it after nearly 5 months.

That sounds a bit or a lot like what used to happen with Fords from 1980s/1990s, in as much, as when when the stiction on the locking mechanism became different enough across a car "lock set", with normal central locking ie not remote, you unlocked the driver's door and the car immediately relocked, so while this was happening, the plan was to get prepared and grab the door handle as soon as the key had been turned to unlock the car. The fix for them, having simple solenoid locking mechanism was to check the protective rubber gaitor on all locks and reposition any that had moved along the linkage as that meant that the gaitor(s) that had moved were now starting to become fully compressed before the unlock had happened.
On a similar vein, was there not a possible issue with all VW Group car lock mechanism where ending up with a mix of lock mechanism suppliers locks on a car could end up with this continuous "cycling" of the locking mechanism - I'm just posting this in case that situation is now forgotten.

 

[mjstokes85]

That's all I can think of, I've now seen videos 2 other Ibizas, not just Cupras, that have this locking over and over again issue with one door. Seeing as it's not the CCM units, it's probably not the wiring, it's not the actuators as they are brand new and it did it with the old ones, I suspect it's the door alignment. I've certainly seen this issue appear on VW forums and Audi forums too, just never seen them get to the point that they melt 2 units.

 

[RUM4MO]

I'd guess so, any misalignment could cause a lock module to fail to achieve "its task" so give rise to "cycling", in the same way that differing manufacturers of locking modules within a car - and the same as my tale about older Fords ending up with the rubber gaitor moving along and compressing even when in what should have been the extended state.

It is very annoying being on the receiving end of unusual faults, been there done that, and got annoyed when everyone told me I had the wrong end of the stick sort of thing!

 

[mjstokes85]

Hooked up VCDS lite with a cheapo ebay cable to confirm auto lock is turned off, so took it for a spin, all good, car doesn't try to lock and I can lock it with the remote still, result. Now I have an issue with the heated mirrors not working, I suspect Seat have changed the BCM code and not added them back in, so I either need to take it to Seat again, who I know won't have a clue how to do that, or buy a genuine VCDS licence and code it myself.

 

[RUM4MO]

I suppose it depends on your future motoring plans, if staying within VW Group as far as cars are concerned, buying into VCDS will work, but, maybe look online for older genuine versions of VCDS interfaces as full coverage for your car and full ability for coding will be provided with the original VAG-COM interface, really down to relative prices and you will only find that out by looking. Even buying a genuine used VCDS HEX+CAN USB will take you up to roughly 2018. I only upgraded to the later VCDS HEX - V2 version after my daughter bought her May 2019 SEAT Leon Cupra. So things to consider are going to stay within the VW Group should include, if you buy from a genuine UK based VCDS reseller, then they will allow you to upgrade in the future by trading in your old still working interface - but their value will be lower than you can buy a used genuine one online, so if you are the sort of person that is willing to sell a bought used VCDS online and then buying a later one then buying from a UK VCDS reseller is not for you - I'm a wimp when it comes to selling things, so I took the easy but more expensive route of trading older versions back into my original supplier, my loss!

 

[mjstokes85]

I sorted the mirrors! They now seem to be linked to the rear de mister! Apparently this is a VCDS setting that can be changed so they are working, just not as before. I went to get a new battery for my car today as that was screwed and I’m back up and running in the Cupra, feels good! Just needs a good clean now.

 

[RUM4MO]

That is probably the safest way to have them working, all my non VW Group cars used to have the mirror heaters controlled that way. The only trouble with that is I've experienced during certain weather conditions, driving in to town from the countryside in early morning and the "very cold but clear" mirror glasses suddenly misting up when driving into/through an area where the air is warmer and so wetter, so a quick flick of the mirror heater switch sorts that out - while the rear screen stays clear.