# Heated rear screen



## SLine_Tom (Oct 20, 2017)

My rear screen seems to take forever to clear, E.g. on my way into work this morning after 40mins it still wasn't fully clear. It seems to start clearing from the drivers side bottom corner.

Anyone got any ideas, or is this just another thing I'm going to have to have a moan at the garage for ?


----------



## tttony (Dec 21, 2014)

All the "lines" should warm up at the same time and pretty quickly. Sounds like there is a fault with yours.


----------



## SLine_Tom (Oct 20, 2017)

I thought as much, but didn't know if this was another quirky TT issue. Guess I'll be out with the anti-freeze again tomorrow morning. :roll:


----------



## ldhxvs (Aug 18, 2016)

It's the same with mine, it takes forever to clear. Mostly it never clears fully at all.


----------



## SLine_Tom (Oct 20, 2017)

If I find the cause I'll let you know.


----------



## ldhxvs (Aug 18, 2016)

PossibleTT said:


> If I find the cause I'll let you know.


Much appreciated!


----------



## Sodde (Jun 1, 2015)

I had my rear screen replaced on my 2012 TTS with I bought in 2015 under a Audi certified used warranty because the actual elements were 'unsticking' from the glass and overheating causing the line to fail. I did'nt really notice it until we got to the colder weather. If I looked closely I could see air gaps between the element and the glass kinda like a poorly applied sticker.
Glad I didn't have to pay for this one, when I asked the 'Stealer' how much is was, he said around $800.


----------



## AndreiV93 (Mar 29, 2017)

Mine stopped working completely on my Roadster.

I need to have a look at it but I have to take the roof lining off which looks like a pain in the back side :lol:


----------



## SwissJetPilot (Apr 27, 2014)

This might be of interest while you're at it. Permatex makes a trace repair kit available on Amazon

https://www.frostfighter.com/defroster- ... -guide.htm

https://www.amazon.co.uk/Permatex-09117 ... atex+09117

And a Youtube "How To" for using Permatex 09117






Product information...

https://www.permatex.com/products/speci ... epair-kit/


----------



## SLine_Tom (Oct 20, 2017)

Thanks, ill have a look at that.


----------



## Steve in Ireland (Oct 13, 2017)

SwissJetPilot said:


> This might be of interest while you're at it. Permatex makes a trace repair kit available on Amazon
> 
> https://www.frostfighter.com/defroster- ... -guide.htm
> 
> https://www.amazon.co.uk/Permatex-09117 ... atex+09117


Thanks for that. It turns out that I have one track broken... directly at eye level.


----------



## SwissJetPilot (Apr 27, 2014)

Hope that helps.  Just mind the temperature when you do the repair. According the instructions...

_"Repairs can be made ideally at temperatures from 50°F to 75°F (10°C to 24°C)."_


----------



## SwissJetPilot (Apr 27, 2014)

Did you guys manage to get your defroster traces/connector repaired? Curious if the Permatex was a good solution or if you went with something else.


----------



## pazaz29 (Oct 10, 2016)

.


----------



## SLine_Tom (Oct 20, 2017)

I kind of gave up and decided to just deal with the slow clearing screen


----------



## pazaz29 (Oct 10, 2016)

Well I can now see why mine is not working. I lowered the roof a bit, so I could bend the lining up and get my hand underneath. Where the roof frame is by the rear window, there is a black cable that has broken / snapped off and I am assuming that this is the Heated window cable explaining why mine has no life. I cannot see where it has broken off from though.


----------



## pcbbc (Sep 4, 2009)

Not a lot of use, but might help.
Exploded parts diagram - Item 20

Edit: Opps  That's the MK1 diagram. Doesn't seem to be present on the equivalent MK2 diagram. :?:


----------



## SwissJetPilot (Apr 27, 2014)

@ pcbbc - Close!! So close.... 

It's over in the Electrics section.

https://audi.7zap.com/en/rdw/audi+tt+tt ... 71-972070/
.


----------



## davidmy6156 (Jun 25, 2019)

Hi there have a non functioning rear heater too on my roadster. Checked the continuity across the rear window element - OK
checked the fuse and switch - OK too. switched on and don't have 12v at the window connectors when I checked at the side of the rear window....... The wiring away from these seems really awkward to trace. Anyone know where they go? into the boot compartment or from the glass/hood, down the rear side panels? I read there was a relay somewhere?? Help greatly appreciated as the cold and frost approaches!!


----------



## TTsdsgomg (Mar 19, 2013)

davidmy6156 said:


> Hi there have a non functioning rear heater too on my roadster. Checked the continuity across the rear window element - OK
> checked the fuse and switch - OK too. switched on and don't have 12v at the window connectors when I checked at the side of the rear window....... The wiring away from these seems really awkward to trace. Anyone know where they go? into the boot compartment or from the glass/hood, down the rear side panels? I read there was a relay somewhere?? Help greatly appreciated as the cold and frost approaches!!


I seem to remember that the roadster switches the heated rear screen off if its on when putting the roof down so might be something to do with that :?


----------



## JohnnyFarmer (Aug 19, 2016)

Does the heater indicator light in the switch come on when you switch it on? When my roof is down the element does not come on but neither does the light (or maybe briefly) - Both work normally when roof is up.


----------



## davidmy6156 (Jun 25, 2019)

Thanks chaps... Have given that a go with 
1] ignition on, hood up, heater switch on, light on - no heat
2] ignition on, hood down, heater switch on, light on - no heat (fortunately!)..... Hmmm just think I need to follow wiring through to appropriate connectors or relay? 
I wondered if I could check also using a direct fused 12v between the window connectors themselves - just to eliminate switches harness etc., etc.,??


----------



## aviatoratrg (Aug 4, 2019)

Hi, did you trace the wire ? I have the same problem, no power at the wire to the rear screen. The switch light up and the 25A fuse is fine.


----------



## JohnnyFarmer (Aug 19, 2016)

Hi David this is the behaviour for my rear screen element/switch. - Good luck -

https://1drv.ms/v/s!Al-SJohhR4ZogfAGCcDRRS7Ywqbgtg

Is yours is effecting the behaviour of the indicator light ? Next time I'm in the car I'll listen for the relay again get a rough idea where it is. SJP may well have a schematic for the wiring/relay location. Remind us do you have a VCDS scan?


----------



## JohnnyFarmer (Aug 19, 2016)

David - Found it - I think the relay is in the CECM If that's what Audi mean by 'onboard power supply control unit'


----------



## SwissJetPilot (Apr 27, 2014)

On Roadsters, the heater rear window button E230 is is disabled when the top is down via Control Unit J519. 
Reference Self Study Program SSP391 (it's in the Knowledge Base).


----------



## Petar92 (Sep 29, 2019)

Hey guys, since Im having issues with upper part of defroster, ( top 10cm of rear windshield), not working , but the rest of glass defrosts, I looked it up and found bunch of gaps in the lines.
I made a couple of pictures of my glass, going from lefthandside towards right, and labeled my gaps 1.-10.
Could you please compare it to yours ( if 100% working) and tell me which gap nummbers should NOT be there?

I made 5 photos, A,B,C,D,E,
And marked middle of the car with RED line.

Thank you so much for answers!

Once I have all the gaps I need to fix, I will fix it with amazon repair kit and will let you know
If it works!


----------



## SwissJetPilot (Apr 27, 2014)

From: SSP 382 Audi TT Coupé '07 - Electrical & Infotainment (can be downloaded from the KB)

It may be that not all the traces in the Coupe rear glass are for the defroster -

*Aerials*

_Only the aerial modules required for the existing equipment are fitted in the vehicle. In the Audi TT Coupé '07, most aerials are integrated in the rear window. Only the navigation aerial (GPS), the telephone and digital satellite radio (North America only) aerials are integrated in the roof aerial.

The amplifiers for the various systems are fitted at the top left and right, as well as the bottom right of the rear window. The bottom right aerial module is available in variants for phase diversity and switched diversity. Various FM aerial systems are installed in the vehicle to serve the various radio tuner systems. Radios with phase diversity for FM reception (= chorus, concert or symphony radios) have a different FM aerial system to radios with switched diversity (= Navigation plus (RNS-E) or Navigation (BNS 5.0))_


----------



## Petar92 (Sep 29, 2019)

Thank you SwissJetPilot!!

Okay, it helps a bit. So 1,2,3,8,9,10 are definitely factory breaks, but inner ones should be connected, as far as I can see.. 

Can you please tell me what is SSP and KB? 
Thanks!!


----------



## SwissJetPilot (Apr 27, 2014)

The "KB" is the forum Knowledge Base. "SSP" is a Self Study Program, of which there are many, published by VAG (Volkswagen Audi Group). You can find SSPs and Workshop manuals (along with a ton of other useful information) here in the KB -

*FAQ - Audi TT (8J) Workshop Manuals & Self Study Programs*
https://www.ttforum.co.uk/forum/viewtop ... &t=1833829


----------



## Petar92 (Sep 29, 2019)

SwissJetPilot said:


> The "KB" is the forum Knowledge Base. "SSP" is a Self Study Program, of which there are many, published by VAG (Volkswagen Audi Group). You can find SSPs and Workshop manuals (along with a ton of other useful information) here in the KB -
> 
> *Workshop Manuals -*
> https://www.ttforum.co.uk/forum/viewtop ... &t=1833827
> ...


Thank you so much for endless help !!


----------



## pcbbc (Sep 4, 2009)

My educated guess is that those top 3 horizontal lines, the ones that aren't connected to a thick trace on the left hand side, are purely there for the aerial functions. i.e. They're not designed to heat the screen at all.

And I think all of those breaks are probably meant to be there (aerial design is somewhat of a black art) and I would think very carefully (e.g. check against another vehicle) before deciding to repair any of them.

The lower section are designed for the heating function (combined with some FM aerial functions also). That much is indicated by the thickness of the traces necessary to carry the required current.


----------



## SwissJetPilot (Apr 27, 2014)

You might want to go out on a nice cold, icy morning, take a picture of the rear window iced or fogged up. Then put on the defroster and watch what happens. Post it, and see if anyone else has a similar pattern.


----------

