Windscreen wipers stopped working after Diagnostic

[Jake458]

This should be good, I have had 2 auto electricians have a look at this, rang loads of different garages (some french specialists) and they cant fix it so this is my last resort.

I bought a 407 SW 2.2 petrol 2005 (55) and went to get a diagnostic done to see what was wrong with the car, came out the garage and 2 days later tried to clear the front windscreen and the wipers wont budge, told me to buy some replacement wipers so I bought a passenger side one and fitted it and nothing changed, then bought a driver side motor and same thing nothing changed.

Took it back to the guy and he had it for 2 days, checked everything and its all there no breaks in the wires or bad fuses (checked for a LIN signal with an oscilloscope the lot), so he came to the conclusion its the Underbody control unit.

(Fault code F02F: absence of communication with the windscreen wiper ECU : Not characterised.

So I then took it to another auto electrician and hes had it for 2 days and hes saying its the wiper motors that are bad.

Im seeing some mixed opinions on if the wipers need coding to the car and when I rang a bunch of different auto electric specialist garages and even french specialists one would say different than another.

Everything else on the car works that is essential (auto lights etc.), it has the proper bulbs in from what I can tell as the wipers worked just fine before the diagnostic.

Am I on a lost cause or is this a making mountain over a mole hill type deal.

Otherwise its for the scrapper, thanks in advance for the help.

[mickthemaverick]

I'm sure one of the more technically aware members will reply in due course but in the meantime have you carried out a BSi reset since the diagnostic was done? This is the procedure: viewtopic.php?p=601679#p601679 good luck!

[wurlycorner]

Difficult to believe it can be 4 defective motors…
Very basic question… you say they’ve scoped the data comms to confirm they are working ok, but have they checked powers and grounds throughout the system?
And check grounds for ability to carry actual current, not just continuity?

[Hell Razor5543]

I had something like this happen when I made this mistake of starting the car when the wipers were going through a single pass. They stopped, and would not respond the the wiper control. However, when I pulled and re-seated the relevant fuse (in the engine bay fuse box) it caused the wipers to reset, and they then worked properly.

[Jake458]

Thankyou all for your quick responses, all I was told was that all the "ingredients" so to speak are there for the wipers to work.

The timeline is that I took it for the diagnostic, then because of the dry weather we were having I didnt notice until 2 days later, the following week took it to be looked at by the same guy.

Its getting 12v to the plug I checked myself, and I even saw when I took it to the first guy who did the diagnostic he plugged into the car, and when you change the mode on the stalk it was registering it on the diagnostic machine as well on the dash screen in the car (when it went from man to auto).

He came back to me after he had it for those 2 days and said all the "ingredients" so to speak are there, he said he cleaned the grounds, im assuming the ones he could get at as I think theres one under the bumper, checked the LIN signal and such and said its all good but the "BSI sends the signal to the UCU and its not sending it to the wipers".

I was skeptical also about the motors as ive been on here a few times and seen others have had wipers slowly degrade or one stop working, but not 2 at the same time just drop dead, but im still being advised to buy another 2 and a Underbody Control Unit that I managed to find with the same part numbers, but theres only that one for sale unfortunately so ive pulled the trigger on that and crossing my fingers at the moment.

Is there a way to test the motors? Or do they need a signal

[Hell Razor5543]

I have seen (on this Forum) posts where people have found the magnet used to detect the wiper position had come away from the spindle, and when they glued it back into place (using a suitable glue) the wipers started working again.

[Jake458]

I have seen (on this Forum) posts where people have found the magnet used to detect the wiper position had come away from the spindle, and when they glued it back into place (using a suitable glue) the wipers started working again.

Is that on the motor itself?

[Hell Razor5543]

You would have to look for the right posts, but I believe it is on the spindle within the motor casing. More than that I cannot say, as I did not take proper notice (as I have not had a vehicle with that style of wipers).

[mickthemaverick]

You may find some pointers if you read through this thread, although not the same car some aspects are similar: viewtopic.php?p=566496#p566496

[wurlycorner]

and said its all good but the "BSI sends the signal to the UCU and its not sending it to the wipers".

If they're saying that, then I don't understand why they're also recommending changing the wipers - seems pretty conclusive that the fault is at the UCU.

When you get the replacement UCU (but before changing it) I strongly suggest you check all the relevant power and grounds are there and properly functioning and that the contacts are in good order at the plug/ECU module.