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D2 - Interior Electrics Airbags, Sensors, climate modules, instrument clusters, switches etc

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  #11  
Old 6th December 2020, 10:26 PM
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Originally Posted by hunker7 View Post
I think that's the next step, take off the module and have a good look at it. There are 4 wires, 2 from battery to control unit and then 2 that go to windscreen I take it?
Not quite. One is a control line from the HVAC unit, which I assume is the connector on the left of the picture. The brown and red cables (thinner than those from the battery) go to the windscreen itself and split in two somewhere as there are two connections at the top and bottom, which probably eliminates the possibility of a fuse under that cover.

I suppose to cover everything you could start the car, switch on the front demister (assuming it's cold) and then check if the boot module is putting out any power. If it is then that should eliminate the control line from the HVAC unit, the HVAC unit itself and the boot module, with the possibility being a break in the lines going to the screen - Just thinking, with VCDS, you might be able to check the measuring blocks to check what the temperature sensor is reading (since that is part of the criteria). A continuity check of the lines going to the screen would be next but would be awkward considering the extremes (from boot to windscreen), and then there is getting access to the lines at the windscreen end. The top ones you can get to by removing the overhead panel, but the bottom ones are somewhere near either corner, unless you can find them somewhere around the base of the A-pillar.
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2001 A8 D2 FL 3.7 Q - LPG Conversion, Engine: AKC, Gearbox:FBB, Colour:LY5X Aqua Blue pearl effect, Interior:WJ light beige/dark beige valcona leather with burr walnut inserts

My DIY jobs - Replaced alarm horn, Replaced Coolant Temp sensor, Updated RNS-D firmware, Installed Reversing Camera and Digital TV, Dashcam Installation, Retrofitted Rear Blinds, Auto-Dimming Rear View Mirror, Chrome Boot Struts

Sold! 2008 S8 D3 5.2 V10 - Engine: BSM, Gearbox:KLW, Colour:LY7F Suzuka Grey Pearl Effect, Interior:Black/Black with Silver/Black valcona leather with carbon atlas inserts, Bang & Olufsen, Heated windscreen, Soft-close doors, TV, DAB, AMI, Quad Zone, Auto Boot, Auto dim Mirrors, Keyless entry, PDC with rearview camera, AFS II Headlights

My DIY jobs - Fan Jet Windscreen Washers, Retrofitted Electric Side Blinds
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  #12  
Old 7th December 2020, 10:08 PM
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Originally Posted by HPsauce View Post
It was a pretty rare option.

Back then the patents/licences for it were almost all held by Ford which is why they had it relatively widely available, even on my 1998 Focus (one of the first out of the factory).

I presume Audi decided to pay the fees to Ford for their premium model range. And I'd guess Ford would be happy to take the money as they had no competing model.
The Ford system has visible wires inside the glass, which can be a tad distracting in night-time headlamp glare. It was used in aircraft during WW2 so perhaps any patents have expired. I actually have this on a VW.

The Audi system energises a tin dioxide layer that is deposited on one of the inner surfaces of the laminated glass. When a current is applied across the glass resistance in the metallic layer causes it to heat up, and in turn warms the glass.
IMO it's the best system out there. Very fast and invisible.

BTW your engine needs to be on for the heated front screen to operate.
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  #13  
Old 8th December 2020, 05:33 PM
hunker7 hunker7 is offline
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Quote:
Originally Posted by tonupkid View Post
The Ford system has visible wires inside the glass, which can be a tad distracting in night-time headlamp glare. It was used in aircraft during WW2 so perhaps any patents have expired. I actually have this on a VW.

The Audi system energises a tin dioxide layer that is deposited on one of the inner surfaces of the laminated glass. When a current is applied across the glass resistance in the metallic layer causes it to heat up, and in turn warms the glass.
IMO it's the best system out there. Very fast and invisible.

BTW your engine needs to be on for the heated front screen to operate.
Found your explanation very interesting, the whole system just screams German

Engine is on but nothing, next day off that control units is coming out for inspection
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  #14  
Old 10th December 2020, 12:07 PM
hunker7 hunker7 is offline
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I do hate people sometimes

So I have figured out why heated screen doesn't work....

How does one go about fixing this?
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  #15  
Old 10th December 2020, 12:26 PM
MikkiJayne MikkiJayne is offline
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You don't I suspect you have a standard screen in there now as the heated one is no longer available. Those connectors were likely cut off when the screen was replaced.
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  #16  
Old 10th December 2020, 12:36 PM
hunker7 hunker7 is offline
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Originally Posted by MikkiJayne View Post
You don't I suspect you have a standard screen in there now as the heated one is no longer available. Those connectors were likely cut off when the screen was replaced.
Is there any way of checking?

Some have said that heated screen has purple tint which mine has
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  #17  
Old 10th December 2020, 12:39 PM
hunker7 hunker7 is offline
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To me they seem to have been ripped off (or at least that's what I'm hoping for) 0
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  #18  
Old 10th December 2020, 12:48 PM
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Not sure if it's helpful, but the attached image shows the information on mine. No part number unfortunately.

I suspect the only way to be absolutely sure would probably mean removing the headlining to see where they originally connected to... if it's still the original screen.
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2001 A8 D2 FL 3.7 Q - LPG Conversion, Engine: AKC, Gearbox:FBB, Colour:LY5X Aqua Blue pearl effect, Interior:WJ light beige/dark beige valcona leather with burr walnut inserts

My DIY jobs - Replaced alarm horn, Replaced Coolant Temp sensor, Updated RNS-D firmware, Installed Reversing Camera and Digital TV, Dashcam Installation, Retrofitted Rear Blinds, Auto-Dimming Rear View Mirror, Chrome Boot Struts

Sold! 2008 S8 D3 5.2 V10 - Engine: BSM, Gearbox:KLW, Colour:LY7F Suzuka Grey Pearl Effect, Interior:Black/Black with Silver/Black valcona leather with carbon atlas inserts, Bang & Olufsen, Heated windscreen, Soft-close doors, TV, DAB, AMI, Quad Zone, Auto Boot, Auto dim Mirrors, Keyless entry, PDC with rearview camera, AFS II Headlights

My DIY jobs - Fan Jet Windscreen Washers, Retrofitted Electric Side Blinds
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  #19  
Old 10th December 2020, 01:05 PM
hunker7 hunker7 is offline
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Quote:
Originally Posted by steamship View Post
Not sure if it's helpful, but the attached image shows the information on mine. No part number unfortunately.

I suspect the only way to be absolutely sure would probably mean removing the headlining to see where they originally connected to... if it's still the original screen.
Very similar info, apart from mine being IR and yours is IR-H
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  #20  
Old 10th December 2020, 01:33 PM
MikkiJayne MikkiJayne is offline
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The purple tint is just the heat-resistant coating - both types can have that.

If they have somehow been torn off a real heated screen then there is no way to reattach. IIRC the connector tails are bonded to the coating on the screen right at the edge. You'd have to take the screen out to see if the pads are there for the tails, which would destroy it, heated or not. The lower connections are at the outside corners so it may be worth taking the lower dash or glovebox off to see if you have the same torn tails at the corners as well. The tails get caught in the screen adhesive so I think it is very likely they came off when the original heated screen was removed.

It seems to me like IR-H is heat-reflective (InfraRed), heated, and IR is just heat-reflective. The German translations use the same letters (infrarot, heizung).
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