Windowscreen wipers front working sometimes, then not again

[PhiloB]

Hi,

 

This is my first post here, but I've found a lot of help on the forum in the past, so first, thanks for that!

 

My front windscreen wipers stopped working while driving (when using the screenwash - it wasn't raining). When I stopped I pressed in all the fuses (as I didn't know then which was the right fuse and a few days earlier had an issue with a brake light fuse that was loose). Then it worked again when I started. Yesterday it suddenly stopped again while it was raining so less fun. Stopped the car, ten minutes later it worked again briefly before stopping again, came on for two wipes later and then nothing. This morning, they are working again.

 

Fuse (#44) is ok.

 

Saw some other topics that talked about the relay (Front Wipers Stopped - Skoda Fabia Mk II (2007-2014) - BRISKODA) but can it be that if the wipers sometimes work and sometimes not?

 

Could it be a loose/corroded cable/connection? Where to start looking? In the post mentioned above, Paullyie's problem was a bad earth, but where would that earth be? 

 

Any help or ideas much appreciated. 

 

Seb

 

[PhiloB]

Hi, I should probably add that when it works, all settings (intermittent, normal, fast) are fine, and when it doesn't, nothing goes, also when I spray the window (wash does spray, but the wipers don't go).

 

Thanks again,

 

Seb

[anton]

This probably wont help apart from a bump but on my intermittent indicator fault  i started on the first process in the chain and that was spraying the switch with electrical cleaner ,then  i looked under that fuse box to check connections to the bcm ,i also did a phone video to have a good look around where ii couldn't see.

then i  checked the earths i could find ,the obvious main one ,and one on the inner wing down below the battery

[Breezy_Pete]

Quite possibly the relay inside the BCM.

There's a guide to replacement in the Fabia Guides section.

Soldering involved.

Yours will be the BCM with part number suffix F, the second relay type mentioned in the guide.

[PhiloB]

Thanks very much Anton and Pete for your quick answers!

 

Anton, sorry, I am not a seasoned home mechanic. Where is the obvious main earth located on a Roomster?

 

Pete, I saw that guide you wrote, but I am also not a seasoned solderer (at all), so I guess my best bet would be to and find a second hand BCM if that's it. If I let a mechanic read the car out, would that pick up a faulty relay (also if it sometimes works and sometimes not)? Would be a shame to replace that if it wasn't the problem. 

 

Thanks again!

 

Seb 

[26DIPP]

Hi,

 

We had the windscreen wiper fault. I tried soldering first and then changed the BCM. You will not find a fault code on read out for this as it is a relays fault

[PhiloB]

Thanks 26Dipp!

 

That's good to know. How did you know it was the relay that was faulty? Did you get a second hand BCM? 

 

Cheers,

Seb

[PhiloB]

I found the workshop manual for the Roomster in a post by @Graham62 (thanks!) and found the "Onboard Supply Control Unit" in there, but there is a warning saying: 

 

Quote

"When replacing the vehicle voltage control unit - J519- , if
necessary the data bus diagnostic interface - J533- , the ⇒ Vehicle
diagnostic tester must be connected before removing the
control unit and the function “Replace control unit” must be
selected in the operating mode “Targeted fault finding”. Then
code the new control unit after the installation see ⇒ Vehicle
diagnostic tester"

 

Does this mean I shouldn't take it out myself (I don't have a diagnostic tester)?

 

Saw in @Breezy_Pete guide that some relays have visible damage and in another post that BCM terminals can be corroded (@mrgf) I had some damp issues with the car after leaving it parked at an angle over Christmas, so thought that may be an issue too.

 

I'll start by taking the wiper motor out though and checking the connections there (not today unfortunately, pulled my back:( - shame because a nice day here in Argyle). 

 

Thanks again!

[Breezy_Pete]

@PhiloB whereabouts are you based? 

There's a way of testing the motor by just shorting two of the contacts of one of the plugs that goes onto the control unit, immitating the relay being energised.

Possibly not going to be easy with a bad back though.

Coding a replacement control unit (on a pre-March 2010 built car) is very easy, just one 5-digit code to read out of existing and drop into new one once installed. Registered copies of VCDS Lite can do it, as well as full VCDS.

Another control unit might have a relay with contacts that are also worn out though. Can't remember if I have one at the moment and can't check this week.

 

 

[PhiloB]

Hi Pete, 

 

Thanks a lot for all your advice! Really appreciate it.

 

I'm in Scotland in Argyle (so need reliable wipers, but it's a car we don't use every day). I'll wait a bit for the back to get better before doing anything though - it doesn't like those awkward positions...

 

The tricky thing is that the wipers sometimes work and sometimes cut out completely, which makes it harder to find the problem. I haven't discovered any pattern yet. The first time they cut out was a dry cold day a few weeks ago when I wanted to spray the window, then came back on later when I had stopped and restarted, but I just tested for one wipe.  The second time was last week while it was raining, working fine for 10 minutes, then suddenly cutting out, coming back on very briefly after stopping the car for a while, then stopping, then giving two more wipes before cutting out again for the rest of the drive; next day, they worked and so far every time I tested up to now, but haven't tested in prolonged rain again. I had it on intermittent wiping on Sunday for a while in a light drizzle and it worked just fine. Does that sound like a relay? Someone else told me relays either burn out or not, so a faulty relay wouldn't sometimes work and sometimes not. I read in your post that relays take a beating on the intermittent setting, which worked Sunday. Can it still be the relay if it works like that?

 

If it is the control unit that's the problem and you have one that works and I could buy it, that would be great of course! No rush, I will probably give my back a week to recover before digging in again. Sorry if these are silly questions, but do you read out the unit itself or do it through the general fault diagnostics plug of the car? Just wondering if I could take just an old and new unit to a garage with VCDS to get it read and programmed or whether I'd need to let them replace the unit. Good to know what's needed!

 

Cheers again,

Seb

 

 

[Breezy_Pete]

I'm away this week anyway, but it sounds like a relay change by post might be feasible with a bit of planning.

 

Code read/write usually done via the diagnostic port, but unnecessary if relay is changed on original unit.

 

Not too sure how to eliminate all other possibilities,  but intermittent  work/not work wouldn't surprise me with burnt contacts.

 

[PhiloB]

Oh wow, that would be great if that would work. Shall I try to look at other possibilities and if I find nothing and the problem returns, then I contact you again?

 

If that's ok with you, is there a way to contact you directly, or do you prefer me picking up this post?

 

I'll follow up here with how I get on in any case.

 

Cheers,

 

Seb

[anton]

On 18/03/2024 at 09:37, PhiloB said:

Thanks very much Anton and Pete for your quick answers!

 

Anton, sorry, I am not a seasoned home mechanic. Where is the obvious main earth located on a Roomster?

 

Pete, I saw that guide you wrote, but I am also not a seasoned solderer (at all), so I guess my best bet would be to and find a second hand BCM if that's it. If I let a mechanic read the car out, would that pick up a faulty relay (also if it sometimes works and sometimes not)? Would be a shame to replace that if it wasn't the problem. 

 

Thanks again!

 

Seb 

 

Bah still not getting notifications, the ones i meant is the main earth from the battery and one from the body to the engine block its probably rubbish advice but i went on an earth hunt with my indicator problem , its amazing how the infomation i was after just didnt seem to be on google, i miss the physical haynes manuals as well tbh 

[PhiloB]

Thanks Anton! 

 

Did you solve your problem in the end (and what was it)?

 

Cheers,

 

Sebastiaan

[anton]

It's a few threads down , indicator glitch, basically it's becoming better over time so I live with it, maybe I had moisture on the bcm don't know but I miss the days of just plugging a new relay in !!

[PhiloB]

Yes, that would be nice!

[26DIPP]

Hi,

 

Pete pointed me to the relays after I had removed and tested the wiper motor and got stuck for options. I got a second hand one.

[PhiloB]

Hello All,

 

Just wanted to give an update. I finally managed to look at the wiper motor and all there looked fine including connector contact. All contacts looked clean (after quite a struggle to get that D connector off ). Since the wipers were working, I couldn't do much else there to test. I also did another test run with the car in pouring rain and drizzle, and it worked fine with all wiper settings (fast, normal, intermittent), so I'll test it a few more times in the rain and see how it goes, before doing anything else. As said there was damp in the car which is now dried out, so I am hoping that caused it. 

 

The wipers did seem to squeak a bit more after reinstalling the wiper arms (also in the wet). Could I have tightened the nuts to tight (don't have a torque wrench)  or done something else wrong on reassembly? I put masking tape to replace the wiper arms in the original orientation.

 

Thanks again for everyone's help here!

 

Cheers,

Sebastiaan