Retro Heated Windscreen - Page 2

tonupkid · #11 3rd January 2010, 08:55 PM

Quote:

Originally Posted by thebluewhale

Thanks for the response Nick

I don't think I've even got a windscreen clear button!
Where is it located?
Is it one of the six buttons on the centre dash above the stereo?

Think so. I have the usual rear window heater button and them somewhat to the left of this, in the same button bank there's the demist front window button. Similar logo to rear, but splayed front window style pict. This is the one that operates the front heater.
Best of luck with it

Oli18 · #12 4th January 2010, 09:24 AM

Not sure i get where this is still either...can you show us? Or better yet, take a picture?...would be interested to see what it looks like. I don't think i have a heated front windscreen...

tonupkid · #13 4th January 2010, 10:00 PM

Quote:

Originally Posted by Oli18

Not sure i get where this is still either...can you show us? Or better yet, take a picture?...would be interested to see what it looks like. I don't think i have a heated front windscreen...

Hi Oli
Apols for my lack of clarity. I was sitting here typing up my answer and it was so frigging cold outside that I wimped out.
Your picture is perfect. The button I press to switch on the heated front screen is the one next to your passenger seat heater. Remember that you will need your aircon set on Auto (looks like yours is not, as I think you will find a yellow light by the word Auto when its on), the outside temp at about +2 or less and the engine cold. At which point, hopefully, a poke of that button will cause its little yellow led to blink slowly for the next couple of mins, whilst the hard stuff on your screen turns liquid and simply runs off. Magic!
Nice weather forcast(er) by the way
Nick

IT · #14 5th January 2010, 11:08 AM

A bit more info from us 'experts'....

The heated screen is quite rare, fitted to less than 5% of cars that we have dismantled.

From the inside, you will see no noticable difference. The heater controls are identical irrespective. The photos already posted show the standard controls which always show a heated screen button, but in cars with no heated screen it just diverts every ounce of heat available directly to the windscreen to clear it quickly. With a heated windscreen, it will clear a little quicker, but not enough improvement to warrant bothering to retrofit in my opinion.

Retrofit involve fitting a new screen (obviously) and also 4 wires, two to the bottom of the screen, and two to the top which then run back to the rear of the car the to the heated screen controller. Also, an output from the climate module that is used to tell the heated screen controller when it is sufficiently cold to be needed.

The only real way to spot a heated screen install (unless you're sad enough to spot the slight purply glaze of the front screen) is to look in the boot. From the factory, they get rid of that hopeless 4 lug divider and put in a decent cover instead:

It way, way better than the normal cover we get (dont know why we dont all get that one) and it is used to do a good job of covering the controller module which looks like this:

Its in the boot to connect directly to the battery, so lord only knows how much current that thing drains !!

Note, it also sits in the gap where the dealer fit rear seat entertainment DVD player goes, so you are unlikely to ever get both squeezed in there...

So, if you have a heated screen, your boot will look like above. If not, then I promise you, you dont

Oli18 · #15 5th January 2010, 01:05 PM

Thanks for clearing that up Ian...

I don't have one (as i'm sure you knew already)!

-Oli

PS - love the purple 8 in the pictures!

thebluewhale · #16 5th January 2010, 04:29 PM

I think I'll give this upgrade a miss then.

For the work involved it's probably not worth it.

notorious · #17 5th June 2013, 04:02 PM

I just retrofitted heated windscreen to my D2 and I wonder if someone knows 'message format' of signal on 'heating request' wire?

My hypothesis I'd that HVAC unit grounds that wire for the period it wants to head the windscreen (or perhaps connects that wire to +12v).

I though to install relay with a manual switch for that thing. With a timer of course.

ToreBj · #18 4th September 2013, 10:24 AM

Quote:

Originally Posted by notorious

I just retrofitted heated windscreen to my D2 and I wonder if someone knows 'message format' of signal on 'heating request' wire?

Hi, I'm getting ready to do the retrofit myself. Were you able to prepare the wiring properly before you changed the windscreen? Or is that something that is better to do while the windscreen is removed? Any practical pointers are most welcome.

notorious · #19 4th September 2013, 02:18 PM

Hello Norway,

I prepared wiring before I removed my old broken windscreen. I see no benefit of working through the opening when windscreen is out.

You will need two wires behind headliner in the area of rear view mirror, plus two more wires in right and left niches for A-pillar foundations.

Make sure you fix two wires in the niches to car chassis. This will prevent tearing off foil from windscreen in case if someone accidentally pull those wires.

Also, when you install A-pillar trims make sure they don't tear off foil by stretching electrical connection. Allow enough length of wire in the niche.

You can find 3 pictures here: http://forum.a8parts.co.uk/showpost....2&postcount=10

On 3rd picture you can see prepared wire in the A-pillar niche, ready to be connected.

Hope it helps. Let me know if you have more questions.

P.S. Heated windscreen is very power hungry. It draws 1000W. Control module that you will install in your boot is able to measure your battery voltage and it will gradually drop heating level from 1000W up to 200W or even switch off heating if your battery is weak and can't maintain voltage during heating. So, your battery should be well charged for maximum effect and should have good capacity. I upgraded my battery to allow heating to work and that involved changing battery tray/well. See this thread: http://forum.a8parts.co.uk/showthread.php?t=3787

Checking alternator and charging voltage would be great too.

ToreBj · #20 5th September 2013, 09:40 AM

Thanks for the very useful feedback. I feel now that I have sufficient overview to carry out the job. Since I got to see the pictures of the windscreen and where to lay the wires I don't have to go to the glass repair shop to verify the connections for the windshield.
I'm aware of the amp draw on this device and due to the fact that I frequently use the Webasto heater during the cold season I have already done some upgrades. I've installed a AGM-battery (Absorbent Glass Mat), which tolerate heavy discharges and will rebuild well. I've also changed my voltage regulator on the alternator to one with an external adjustment. This also has the temperature/voltage compensation giving a higher voltage at low temperatures. I've adjusted it while measuring on the the battery poles until I got about 14.3- 14.4 V. I verified this with the Audi dealership and they said in general the electronics can accept up to 15V. Obviously the voltage will be higher by the engine due to the voltage drop from the alternator to the battery which is in the back. I may have to replace some bulbs more often, but my battery seems to have good capacity whenever I run my Webasto which would otherwise stop due to the low voltage supervison cut-off.

Again, thanks a lot for your feedback!