Berlingo B9 Drivers window

[Slevous]

Hi all.

I have a really odd fault with my B9 drivers window. Turn ignition on without starting the engine and the window works perfectly, start the engine and the window is dead. Testing at the switch and motor I can detect a 5v signal with the engine not running but it disappears when you start the engine. I have fitted a new BSI ( body control module) and the fault is still present. Any ideas?

[Sol]

How did you manage to code the new BSI? This is normally impossible unless the config EPROM is filled with FF and reset to virgin state, then coded with Diagbox. Resetting to virgin is the hard bit for most folk and you can't use a second hand one as-is.

I'll take a look at the window controls in ServiceBox and see what the circuit diagram says.

[Sol]

Ok, so the door ECU pin 3 should go live at 12v with ignition on, via fuse F5 and relay R1 on the BSI. Pin 2 is likely the sense line you found to have 5v on it.

This is the RHS door ECU and main schematics

  B9 Windows.pdf (Size: 130.87 KB / Downloads: 20)

  B9 front right wndw motor.pdf (Size: 85.03 KB / Downloads: 24)

There is a switching arrangement for things like headlights where they are kept off until the engine starts, I would therefore suspect your engine fusebox  PSF1 has an issue somewhere, around the main power relay in the base of the unit. That's what brings on the main consumers with the engine.

[Slevous]

How did you manage to code the new BSI? This is normally impossible unless the config EPROM is filled with FF and reset to virgin state, then coded with Diagbox. Resetting to virgin is the hard bit for most folk and you can't use a second hand one as-is.

I'll take a look at the window controls in ServiceBox and see what the circuit diagram says.

Thanks for the reply Zion.
I sent the BSI off to a couple of repair companies that I usually use but they could not help. Eventually found a company called Ecuexpress who supplied a replacement with the coding transferred from my unit. Lexia shows no related faults except a permanent power missing to the display, although everything seems to be working there.

[Slevous]

Ok, so the door ECU pin 3 should go live at 12v with ignition on, via fuse F5 and relay R1 on the BSI. Pin 2 is likely the sense line you found to have 5v on it.

This is the RHS door ECU and main schematics



There is a switching arrangement for things like headlights where they are kept off until the engine starts, I would therefore suspect your engine fusebox  PSF1 has an issue somewhere, around the main power relay in the base of the unit. That's what brings on the main consumers with the engine.

That's really useful info. Many thanks again. This highlights the problem of electrical repairs on modern vehicles, the relevant diagrams etc. are very hard to come by. Working in the dark is nigh on impossible these days.

[Slevous]

After much head scratching and wiring tests, I finally discovered the cause. The motor control unit, for some reason, has become voltage sensitive. As the voltage reaches around 14.4v with the engine running the window control unit shuts down. I fitted two 20A 60V diodes in series to the motor + pin 3 and it all works perfectly. I have ordered a new motor assembly just to be on the safe side but thought I would post the solution in case it happens to anyone else.

[Sol]

That is a weird one. So you're dropping 1.4v using the diodes in series, taking it down to just below 13v. Good find.

[Slevous]

Using Schottky diodes so dropping to around 13.3v

[Sol]

Ah ok. Electronics man. Same here, unusual solution though.