Rear Wiper Woes

[Argos69]

Hi all,

I'm having a problem with the rear wiper on my C5 X7 2012 Tourer. It started as an intermittent issue (my Wife told me about it, but when I tried it, it worked, so I didn't believe her! ), but it now seems permanent.

The rear wiper doesn't work and I've got this far (see below), but would appreciate any hints before I start suspecting the loom over the tailgate.

Tried the washer, which works fine.
The wiper motor unit itself doesn't appear to be seized and isn't corroded.
I've stripped out the rear trim and disconnected the motor multiplug. I have a good earth on Green/Yellow, Nothing on Pink and 12V+ on the thin blue, regardless of the stalk switch position.
The fuse F1 in fuse box C is ok too.

Are there any relays etc lurking around for me to check?

Don't know if it helps, but when I select the "rear wiping when in reverse gear" under the menu system, it ticks the box for a second, then the tick disappears.....

Any advice warmly welcomed...

[GiveMeABreak]

Check the wiring loom as it enter the tailgate (top rear left corner as shown): There can be failures on the wiring (strains / cracks) where the loom enters the tailgate and check the earthing too. If all seems fine then likely to be the motor - but to be sure you need a diagnostic really. That will be able to detect any fault codes and also check the activation of the motor most likely. You'll need somebody with Diagbox ideally.

[Argos69]

Hi again and thanks for that.

I do actually have Diagbox on an old laptop, so fired it up today for a peek.

There are absolutely no error codes for anything but when I go into actuator tests, the rear wiper can be selected for activation, but doesn't show as working in Diagbox and it doesn't actually start wiping. It does show as "parked".

Back in the good old days, there would be a switch, relay and motor with a couple of wires, but Citroen have found a better way....Thank goodness it's not the front wipers to worry about, with their two synchronised and separate motors with ECUs instead of a linkage!

I will look at the wiring harness over the next few days and see if I get lucky.

Does anyone know if there ought to be 12V+ on the pink wire when the motor is running?

Thanks again

[GiveMeABreak]

There was a common failure with one or more of the front wiper motors which can fail (master / slave relationship) - there was a recall for some of these. I had mine replaced already.

Back to the rear wiper. These are controlled by the BSI now and the relays are integral to it and are not really user serviceable. These are rarely the issue - it is more likey to be the motor or a wiring break I suspect.

Don't get hung up on the colours as these can be random and non-specific. Stick to the wiring numbers printed on hte sleeve every 6 inches or so, but more importantly the pin numbers:

There are 3 pins on the motor wiring plug:
Pin 1: Wire 521: Rear windscreen wiper motor command
Pin 2: Wire 522: Rear wiper motor fixed stop control
Pin 3: M5215: Earth

[Argos69]

Hi Marc and thanks.

After a couple of hours tracing wires and prising trim clips off, I'm not much nearer.

If I put 12V+ on the pink wire the rear wiper starts and works, so the motor's ok.
I traced this wire, using your diagram back to the connector on the rear left below the side window, where pink, turns into grey (you're right about the colours!). At no point does this wire get a 12V+, whatever the switch is doing and the earth is good.
I even bypassed that wire, by feeding a new one through from the connector itself to the motor, just to be sure - nothing.

When I use the stalk switch, I hear a slight click from somewhere in the passenger side of the lower dash.....another mystery!

So for now I'm beaten. The car is a great and economical mile-muncher, let down by questionable technology. This isn'y my first battle with it, (replaced the centre lcd screen and satnav/radio) but I think it's won this one.

If anyone has any other ideas, please shout. Thanks again

[GiveMeABreak]

That click you can hear is the relay inside the BSI controlling the operation (the BSI is in the passenger glovebox on a right hand drive). With these it's not just an on and off, the BSI controls the operation depending on what is going on (like a wipe when reverse gear is selected and times wipe when wash is activated etc. So you'll have the earth and a power wire and also the BSI command wire that controls the operation when it decides.