Technical Ducato Electric Window Diagnosis

[MikeTM]

My first post. I have a 2014 3.0 Ducato motorhome. The passenger window was playing up intermittently and then stopped working in the open position. After quite extensive checks, including removal of the regulator (window motor and winder mechanism), I can report the following:

- I get a click when operating the switch from both positions;
- All fuses checked ok;
- I get 12v at the connector to the motor when operating the switch but only momentarily before it return to 0v;
- The motor spins on a direct 12v battery input when disconnected from the regulator but will not operate when the same 12v is applied with the motor re-attached;
- the regulator moves quite freely up and down by hand with the motor removed;

I’m reluctant to buy a new regulator at the point. Any pointers would be much appreciated. Specifically:

- why do I only get 12v momentarily at the connector to the motor when operating the switch? Is there a current limiting function?

- why does the motor spin on 12v off the regulator but not when re-fitted?

Many thanks in anticipation.

 

[Mike1alike]

- why do I only get 12v momentarily at the connector to the motor when operating the switch? Is there a current limiting function?

Go into the panel underneath control buttons and clean the contacts there. They do get oxidised and start acting like that.
I had a similar thing on my Punto, there are the contacts for the window that stopped working, top right, the driver's window. Voltage on mine wouldn't drop to 0, just about 10 V and window wouldn't move on that voltage.
So try the button contacts first.

 

[Mike1alike]

Also, Welcome to the forum!

 

[Communicator]

Go into the panel underneath control buttons and clean the contacts there. They do get oxidised and start acting like that.
I had a similar thing on my Punto, there are the contacts for the window that stopped working, top right, the driver's window. Voltage on mine wouldn't drop to 0, just about 10 V and window wouldn't move on that voltage.
So try the button contacts first.

If I have understood correctly the above suggests that the door switches operate directly on the window motors. In that case I beg to differ. The switches operate on a controller incorporated in the mechanism. This controller will provide the ability to give the button a long press and then release to fully open or close a window. The controller will also provide the high current cut off facility, which interrupts the motor supply at the end of travel, or when a closing window encounters an obstruction.

@MikeTM asked whether there is a current limit function. He will realise that is what I have described above. How else would you halt the window if it encountered an obstruction? ( I have a very vague old memory of reading about a serious incident, or was it the possibility, of a child being asphyxiated by a closing window.)

A possible explanation for the problem would be the current detector circuit being over sensitive, and operating at normal motor current.

I am attaching an appropriate eLearn print, which was previously posted on forum. See the open rectangles contained within N060 and N061., which are meant to indicate embedded control units.

 

[MikeTM]

Thank you for your helpful early responses Mike1ike and Communicator. The really helpful ELearn document is particularly appreciated. I do agree that the switches operate on a controller/relay which controls the 12v input to operate the motor. And I recognise the current limiter function. If thought that unit was under the dash rather than within the motor/regulator. In relation to that, I am not sure why, when I am measuring the voltage at the motor connector pins (when disconnected from the motor and therefore not affected by window position or load) is only momentarily 12v before dropping to 0 volts.

I’m feeling out of my depth on auto electrics here but will study the ELearn to increase my nous. Also receiving a new regulator/winder mechanism tomorrow to compare its behaviour against mine.

Thank you again.

 

[Communicator]

Thank you for your helpful early responses Mike1ike and Communicator. The really helpful ELearn document is particularly appreciated. I do agree that the switches operate on a controller/relay which controls the 12v input to operate the motor. And I recognise the current limiter function. If thought that unit was under the dash rather than within the motor/regulator. In relation to that, I am not sure why, when I am measuring the voltage at the motor connector pins (when disconnected from the motor and therefore not affected by window position or load) is only momentarily 12v before dropping to 0 volts.

I’m feeling out of my depth on auto electrics here but will study the ELearn to increase my nous. Also receiving a new regulator/winder mechanism tomorrow to compare its behaviour against mine.

Thank you again.

On my x244, you would be correct about the location of the window controller being under the dash. With the x250 model, I would expect 2 relays and some electronics in the regulator assembly.

If as stated, you are going to use the diagram then you may find my attached colour code translator useful, but be warned that there could have been further changes to the diagram between 2006 and 2014. Others may be able to confirm this.