Octavia 90cv electrical door problems

[the_trucker5]

hello everyone.

 

I have a problem that, even though I am a mechanic, drives me crazy because I can't find the fault. Since I bought my Octavia 1U, the passenger door does not work, the light on the window switch on that door does not come on

the window does not work and of course the central locking does not work, it is completely dead.

 

only the speaker works.

 

I have checked the wiring from the passenger's feet to the door, can line ok (3V) and door control unit power supply J387 correct (12v)

 

 

I have gone to the scrapyard and I have obtained:

two door control units (dismantled from an octavia identical to mine with the same phase 1 dashboard and the comfort module identical to the one installed in my car (from a 1997 Passat)

 

Neither by changing the two control units nor by changing the comfort module can the door work.

 

This is exasperating and even more so now that summer is approaching.

 

Note that the other 3 doors work correctly, both the windows and the central locking

 

Can you enlighten me what is the problem? I have to change the lock on the door,? but I would be surprised if that door didn't work because of the lock...

 

thank you very much

Edited 23 April by the_trucker5

[Paws4Thot]

1 minute ago, the_trucker5 said:

I have a problem that, even though I am a mechanic, drives me crazy because I can't find the fault. Since I bought my Octavia 1U, the passenger door does not work, the light on the window switch on that door does not come on

the window does not work and of course the central locking does not work, it is completely dead.

It's most likely a broken core in the driver's or  passenger door wiring bellows. I guess you can cope with fault tracing if you have some idea where to look?

[the_trucker5]

10 minutes ago, Paws4Thot said:

It's most likely a broken core in the driver's or  passenger door wiring bellows. I guess you can cope with fault tracing if you have some idea where to look?

I have disassembled the bellows and I have not seen anything broken even after removing the tape. In the connector of the passenger door control unit, the CAN line arrives correctly (3V as well as the pillar connector (purple cables) and 12V voltage through both the red and yellow-red wires😔

[Paws4Thot]

35 minutes ago, the_trucker5 said:

It's most likely a broken core in the driver's or  passenger door wiring bellows.

Clear now? It's not a broken wire, just the core, so you need to continuity test the wires, not just look at them.

[Breezy_Pete]

Can also be dirty and/or corroded connections at any point. 

Green copper corrosion residue can be the clue to look for.