3.8 8-speed transmission problem - major puzzle, help needed!

[sdocommando38]

Hello guys. There is no way to describe this shortly, so I'll just put an youtube link of my problem here.

what you're seeing is constant, super fast locking and unlocking of the doors + the car dashborad has no idea if it's in P, R, N, D or S.
But there is another part of the problem: when driving, it shifts real late and when it shifts it's pretty rough.

I bought this car by the end of June and it had a problem of late/rough shifting from 4th to 5th gear. other than that it was fine, but the problem progressed now it's doing so when shifting from any gear + what you see in the video.

History of what was done: I took it to the dealership, they ran a computer diagnostics and it showed selector position sensor problem (part number: 427004E000).
We changed this part and the issue persists. the computer still said the same thing.
Now the transmission mechanic says that it is nothing transmission related. The electrician says that we should replace an inside junction fuse box assembly (part number: 919502M511)

My questions are:
1. Has anyone ever had such problem? if yes, how did you fix it?
2. Do you think the electrician could be right and the inside junction fuse box assembly could in fact be causing the symptoms described?
3. Do you have ANY tips at all that could help out?

I drive a lot between cities, not having technical difficulties of this sort is super critical.
Thank you for reading and please send tips if you have any.

 

[EdP]

Hello guys. There is no way to describe this shortly, so I'll just put an youtube link of my problem here.

what you're seeing is constant, super fast locking and unlocking of the doors + the car dashborad has no idea if it's in P, R, N, D or S.
But there is another part of the problem: when driving, it shifts real late and when it shifts it's pretty rough.

I bought this car by the end of June and it had a problem of late/rough shifting from 4th to 5th gear. other than that it was fine, but the problem progressed now it's doing so when shifting from any gear + what you see in the video.

History of what was done: I took it to the dealership, they ran a computer diagnostics and it showed selector position sensor problem (part number: 427004E000).
We changed this part and the issue persists. the computer still said the same thing.
Now the transmission mechanic says that it is nothing transmission related. The electrician says that we should replace an inside junction fuse box assembly (part number: 919502M511)

My questions are:
1. Has anyone ever had such problem? if yes, how did you fix it?
2. Do you think the electrician could be right and the inside junction fuse box assembly could in fact be causing the symptoms described?
3. Do you have ANY tips at all that could help out?

I drive a lot between cities, not having technical difficulties of this sort is super critical.
Thank you for reading and please send tips if you have any.

I honestly don't know if that would fix it but I'd say it is possible. Electrical problems manifest themselves in strange ways and do same things. Intermittent contact could be sending the door lock signals.

If that does not work, there is plenty of information on Exorcism on the internet, could be a solution there.

 

[joegr]

I thought that 2012 was 5 or 6 speed transmission. Did you so how put in an 8 speed from a newer year? Maybe that's the problem?