Wipers do not work on intermittent.

Ozvtr wrote: ↑Thu Nov 25, 2021 12:14 am Have the wipers stopped at a random point on the windscreen or parked at the bottom of the windscreen.

It's a bit of a bazar arrangement. The "wiper power enable" relay sits in the BSM but is controlled directly by a wire from the BSI! The high speed/low speed relay sits in the BSM but is controlled through the CAN BUS from the BSI! Power comes from the battery to the fuse, through the power enable relay to the speed relay and then to the wiper motor. Most of the time ground is provided by the BSI. Power AND ground are switched by relays.

Have you pulled the connectors out of the BSM and looked for corrosion?

What a convoluted way of doing things!

I will check for corrosion today. I only checked the fuses yesterday, and nothing else.
Do you meant these connectors in the engine bay fuse box?

Yes. Check all of the connectors and the pins in the BSI.

Are the wipers parked or at a random point on the windscreen?

Ozvtr wrote: ↑Thu Nov 25, 2021 9:36 am Yes. Check all of the connectors and the pins in the BSI.

Are the wipers parked or at a random point on the windscreen?

They are currently sat at the bottom of the screen in their normal ‘off’ position. However when this fault first occurred and the wipers would only work in ‘Position 2’, they would occasionally ’park’, as you say, in an upright position.

Just checked all the pins in the connectors. None show any sign of corrosion.

As I had to perform another BSI reset after disconnecting the battery, I checked the wiper function again. They temporarily went back to only operating in ‘Position 2’, where they weren’t operating at all the last time I checked yesterday (I guess that means we can rule out the wiper motor itself).
However I tried again about 30 seconds later, and they refuse to budge at all again (the car was running the whole time between the first and second attempts). The front washer function still works though, but with no wipe.

Please excuse me whilst I go and find a brick wall to bang my head against

If the wipers "park" and don't freeze at random positions that's pointing back to the COMs unit. It's pointing to a commanded function and not a loss of power.

The COMs unit will command the wipers to perform a function. As I explained, the BSM and BSI work in conjunction to carry out that function by powering the wipers. If the COMs was to command "nothing" (I.E. a fault), if the wipers were doing something at the time, they will continue to move to a park position and then stop. As opposed to a power failure where the wipers would just freeze at a random point.

There are ribbon connectors in the stalks of the later COMs units that are known to cause problems.

P.S. If you didn't know, the COMs unit is the switching module that has the light and wiper stalks on it.

I thought I’d pop back on here as I got the problem sorted in the end. I took it to a local mechanic who had the Citröen specific software to investigate it. I told him all the symptoms and what I’d done so far, and straight away he suspected the wiper motor was faulty due to water ingress. He said he’d come across it many times.
I left it with him and he phoned a couple of hours later to confirm all the right signals were being sent via the Coms, BSM and BSI, pointing to a faulty wiper motor. He fitted a new one and it worked!

Hang on to that mechanic! Finding one that knows what they are doing is so rare these days.