Lots of problems after mod...

[benjie]

Hi guys, I wonder if anyone can shed some light on this before I take my car apart!

Over the weekend, I re-trimmed my car. I took out the grey headliner and all other associated trim - A, B & D pillar trim etc. I changed it to black. I disconnected the battery due to working close to the curtain airbags. I also disconnected the interior lights in the front & back in order to get them out.

After the re-trim was done, I put the car back together and noticed that the interior lights didn't work and though it was something simple, but then the alarm didn't chirp when I locked the car and the driver's door LED stayed on for 10sec or so.

Also, my heated rear window has always been a bit hit and miss and I noticed when the trim was off the bolt with wires going into the window on the driver's side was very loose, so I tightened it up. Now, then I press the rear window switch the yellow light comes on but then it turns itself off in about 2 seconds.

I plugged it into VCDS last night and here's the fault codes it came up with...

Sunday,23,August,2009,18:52:04:42859
VCDS Version: Release 805.3
Data version: 20090213



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Chassis Type: 8E - Audi A4 B6/B7
Scan: 01 02 03 08 09 0F 11 15 16 17 18 36 37 45 46 55 56 57 65 67
69 75 76 77

VIN: WAUZZZ8E33A321009 Mileage: 143600km/89228miles


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Address 08: Auto HVAC Labels: 8E0-820-043.lbl
Part No: 8E0 820 043 AJ
Component: A4 Klimaautomat 2831
Coding: 00000
Shop #: WSC 00000

2 Faults Found:
00975 - Heated Rear Window (Z1)
38-10 - Output won't Switch or Short to Plus - Intermittent
00975 - Heated Rear Window (Z1)
39-10 - Output won't Switch or Short to Ground - Intermittent

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Address 46: Central Conv. Labels: 8E0-959-433-MAX.lbl
Part No: 8E0 959 433 BC
Component: Komfortgerát T3B 1211
Coding: 07915
Shop #: WSC 63351

Part No: 8E2959802B
Component: Tõrsteuer.FS BRM 0003

Part No: 8E2959801B
Component: Tõrsteuer.BF BRM 0003

Part No: 8E0959801A
Component: Tõrsteuer.HL BRM 0003

Part No: 8E0959802A
Component: Tõrsteuer.HR BRM 0003

6 Faults Found:
01134 - Alarm Horn (H12)
29-10 - Short to Ground - Intermittent
01616 - Signal Wire to Interior Monitor
49-10 - No Communications - Intermittent
01370 - Alarm triggered by Interior Monitoring
35-00 - -
00955 - Key 1
35-00 - -
00957 - Key 3
35-10 - - - Intermittent
00532 - Supply Voltage B+
37-00 - Faulty
-------------------------------------------------------------------------------
Address 56: Radio Labels: 8E0-035-1xx-56.lbl
Part No: 8E0 035 186 J
Component: concert II GRO 0008
Coding: 01005
Shop #: WSC 63351

1 Fault Found:
01317 - Control Module in Instrument Cluster (J285)
49-10 - No Communications - Intermittent

End ---------------------------------------------------------------------


I've obviously knocked some wire out when putting the trim back on, has anyone got any ideas with this before I take the car apart again?

[benjie]

BUMP... Anybody?

[Woorlord]

Check the rear demist (30A) fuse - if the wires were loose they could have shorted and blown the fuse.

What happens when you reset the DTC's and then operate the rear demist?

Silly question - is this the original A/C unit - has it ever been changed?
I upgraded mine from a Single DIN to Double DIN 18+months ago and only recently realised that it was not 100% compatible, think I needed a B6 one and had a B7 one. Had the exact same error codes. Had to rewire the rear demist to switch through a 30A relay - works fine now and no errors.

What are the errors now on the Convenience Module ?
Some of those errors, (Interior Monitor) is cause you unplugged the front interior light which also contains the ultrasonic interior sensor. Supply voltage B+ cause the battery was removed, etc. Alram Horn error - are the internal batteries working ?

Elec Windows and locking working OK?

[benjie]

Ha ha! Who's a bloody idiot then? ME! There was a 15A fuse blown and all codes are gone now!

Except the rear window one!

You're right Woorlord, and thanks for the reply, I did change my climate unit about 8months ago, and I think it may have been from a B7 too!
It's doing the thing where you turn it on and it turns itself off after a few seconds. VAG-COM says "00975 - Heated Rear Window (Z1) 38-10 - Output won't Switch or Short to Plus - Intermittent" - Is this the same as you had?

Where did you put the 30A relay? (Not very good with electrics, so laymans terms would be great if possible!)

[Woorlord]

......... You're right Woorlord, and thanks for the reply, I did change my climate unit about 8months ago, and I think it may have been from a B7 too!
It's doing the thing where you turn it on and it turns itself off after a few seconds. VAG-COM says "00975 - Heated Rear Window (Z1) 38-10 - Output won't Switch or Short to Plus - Intermittent" - Is this the same as you had?

Where did you put the 30A relay? (Not very good with electrics, so laymans terms would be great if possible!)

Error reported as you describe and rear Demist light will not latch on.

Have attached circuits of A/C unit connection to Rear Screen with and without relay for you reference - see pdf attachments.

Had an old automotive 30A relay lying around in my garage - easy to obtain from any automotive supplier - very standard.

My Documented Modification:

Required for A/C units where Rear Demist is controlled by slave relay and not directly by internal switching of A/C unit. Bentley circuits suggest A4 models "from November 2004". I can confirm this mod is required for A/C unit part no. 8E0 820 043 BM.

The mod. was pretty straight forward and required a four "blue" female spade crimps, a short length of 1.0mm wire and a 12v/30A automotive relay.

Pull fuse F26 - Heated Rear Window - for safety!!

Pull all plugs from A/C Control unit in centre console.

Sourced a ground off A/C connector D13 - removed the hood casing - Soldered a wire here inside the plug and then remounted the casing. Terminated the free end in a female spade connector and this wire goes to the relay coil.

Undo the taped loom wires to connector "F" - you need to pull back the tape around 2~3inches.

Cut 4mm wire F6 (White/Lilac) around 1.5 inches back from "F" connector.


A/C end - soldered a "thinner" wire to this and terminate in a female spade connector which then goes to the relay coil. This is the control signal.
Car end - put a female spade connector on which goes to one side of the relay switch terminal. This is the feed to the heated window element.

Cut 4mm wire F5 (White/Yellow) around 1.5 inches back from "F" connector.


A/C end - insulate as no longer used to supply 12V/30A to A/C unit.
Car end - (From fuse 226, i.e. Large 30A Fuse in position #26). Put a female spade connector on and wire goes to other side of relay switch.

Re-taped all looms with PVC insulation tape.

Refit all A/C unit plugs.

Refit Fuse F26.

Mod. Complete.

I also cleared any DTC errors with VAG-COM - I tested at various stages to see if relay switched and the rear demits light would stay on before connecting the 12V/30A power feeds! Just to be 100% sure it was going to work!!

Rear Window Demist light should stay on and the glass should get warm.
:beerchug:

[benjie]

Thank you so much, that's a great write up! I look forward to having a working rear window in the near future!

[benjie]

New twist to this now, my interior lighting keeps blowing the 15A fuse! It's not interior monitoring or anything else as I've used a process of elimination. I couldn't be a bulb causing it would it?

[Woorlord]

Take the bulbs out to see!

[benjie]

I have, I think it's the passenger side reading light - both of those reading lights always went in very awkwardly. I can't believe/didn't realise that one bulb can cause a fuse to go!

[benjie]

Woorlord - all fixed now! It was the passenger side reading light blowing the fuse and I did the air con as per your guide above - it was really easy!

One question though, when the rear window button is pressed, the relay clicks into life... but that's not it. It clicks once every 6 seconds - is this normal? (I can hardly hear it when the a/c unit is pushed back into place) The heated rear window works a treat now though, thanks!

[Woorlord]

Woorlord - all fixed now! It was the passenger side reading light blowing the fuse and I did the air con as per your guide above - it was really easy!

One question though, when the rear window button is pressed, the relay clicks into life... but that's not it. It clicks once every 6 seconds - is this normal? (I can hardly hear it when the a/c unit is pushed back into place) The heated rear window works a treat now though, thanks!

I have the same with the switch on and off - I am not sure if this is a standard Audi feature? What I can say is that the rear window does get warm so it should do the job.
I did look with VAG-COM at one of the resepctive monitoring channels and it shows the Rear Demist switching on and off - I guess the only way to confirm is for a B7 owner with VAG-COM could confirm?

Maybe this modulating switch on/off happens to regulate the rear window temperature - after all if it was switched on continuously it would put quite a hefty current demand on the electrical system and your window would get very hot - especially in the current seasonal climate - perhaps it stays on longer with colder outside temps??

[benjie]

Some good points woorllord, I drove to work today able to see out my rear window (without having to wiper it down on the outside either!) I'm very pleased. I think the on and off to regulate temperature/current sounds like a realistic idea.

I'm so pleased! Woo hoo!