Rear screen heater problem

Zitat von David8;67084

Had 3 rear screens replaced in 2 yrs by BMW under warranty because of electrical issues in the wiring.

All very well and good, but 3 years later I then had corrosion appearing because of poor quality workmanship when fitting those screens.

Think in hindsight I'd be inclined to live with a few elements 'out' and not tempt fate with the future demon rust...............

This gets closer to the nub of the matter. The seal on my new window - just like the last one - is "dry" on the outside and I suspect this part of the design might have more to do with the potential return of corrosion than poor workmanship. It seems that even if the window is fitted perfectly, the edges are still exposed to moisture through capillary action, because the rubber overlap is so short laterally. Now on the last one, I had them use a sealant to prevent the dreaded corrosion, but a pal has raised the possibility that this action itself may have caused the premature failure of one of the edge connectors because of lack of ventilation - i.e. it somehow managed to "seal in" whatever moisture was already present. Mmmm! But it wasn't just a few wires that failed after 2 years, it was the whole of the top section, implying a different type of electrical failure. So what's the verdict? I still have a chance to act while the window is perfect and seal the edges against the milkiness that will doubtless recur. Maybe there is some kind of water repellant that would work better whilst still providing ventilation?

Oh NO, Oh NO!!!

Zitat von sprucegoose;67365

But it wasn't just a few wires that failed after 2 years, it was the whole of the top section, implying a different type of electrical failure......

Guys, I know you wouldn't believe this without photo evidence, so check out the pic. This is the new rear screen yesterday morning. Let me re-phrase my previous post: It wasn't just a few wires that failed after 2 weeks, it was the whole of the bottom section, implying a different type of electrical failure!

I took the picture to show Autoglass. When I walked into the local depot in the afternoon I could see from the looks on their faces that they knew trouble was coming - I had the sensation that a turd must experience on being dropped into a swimming pool. Anyway they're on the case and a "technician" is coming round to perform an inspection. Incidentally, as I was discussing it with one of their fitters he let go an interesting disclosure. "Ah, of course we get the screens from the same place as BMW, but sometimes we have to wonder if we don't get the best ones..."

So, whilst I am still quite happy with Autoglass and I know this will eventually result in a satisfactory outcome, the unguarded comment above does raise some questions about whether or not it would have been better to spend £1,000 at BMW in the first place.....

Reinhard, thanks for the extract from the manual. I used the same page when I applied the multi-meter to the wiring on the car. Either you or I have missed something - and I'm happy to be wrong - but please consider the following and let me know if you still think its the car's wiring.

1) Screen fitted August 2007 replaced original which. although milky and corroded, worked (in part) in BOTH sections.

2) Replacement failed completely after 23 months in TOP section. My tests (July 2009) showed:
a) 14.2V coming from the car on BOTH sections.
b) Open circuit across the glass in TOP section.
c) When power supplies reversed, TOP section still not working.

3) Second replacement fitted August 2009 has completely failed in BOTTOM section.

Now, because this is now definitely a warranty issue I cannot afford to touch anything and I don't intend to. But to my mind, the above facts point again to the glass as the prime suspect. Of course its not the only suspect because it is perfectly plausible that the power supply to the bottom section has decided to fail just 2 weeks after my tests. And life is a bitch like that as we all know and such random events tend to throw us off the scent. I am reminded (re ABS) of my earlier quote from Sherlock Holmes - "when you have eliminated all the impossibles, whatever remains, however improbable, must be the truth". So I accept that it might yet prove to be the case that the power supply to the bottom section has indeed failed - and how funny that would be - but the question is this: Given the history, do we think it is likely?

Either way I don't care because it will get fixed. Perhaps we could have a poll on Sprucie's window: Glass or Electrics?

I get to vote first. GLASS!

PS Reinhard, do you think you could remove your photo or reduce it in size as its making the thread difficult to read.

R, I've got both, but the one in the bedroom is, sadly, 4 x 3. Thanks, anyway.

Meanwhile, back to my problem - the glass or the electrics?

Zitat von reinhard;67568

You probably need a new screen.

Ho ho ho, missed the joke the first time!

Faulty Glass, then

The saga is over - for now. At Autoglass's expense, BMW inspected the car and found the bottom near-side connector wire had broken away from the glass - clearly due to old corrosion. So the Autoglass expert then had a look and he agreed. What was not agreed was who was responsible for the faulty part. BMW said Autoglass must have knocked it. The evidence I saw suggested it had happened years ago in one of BMW's storage warehouses. Anyway, thats between them. I told Autoglass I wasn't keen on yet another piece of glass being fitted and that I would be happy with a soldered repair - as clearly there is only one connector that needed attention. They agreed but suggested a conductive epoxy resin instead. So I let them do it yesterday and I am pleased to say that I am now 100% happy with the result. After all, the repair is now guaranteed for life as it counts as "workmanship"! Oh yes, before I forget, Autoglass still had the old one so we had a look at that and guess what? The top nearside wire had indeed failed - but not at the glass, rather the spade end had come off the wire. The same fault - different end of the wire...

Lessons to share:

1) If you buy a new windscreen in the UK (from anyone, including BMW) then make sure it is sound at all connector points before having it fitted. These screens are "old" stock and therefore suspicious.

2) If any of your wires come off, the epoxy conductor resin solution appears to work.

Cheers.