Help with auto climate control, schematics?

[k.alle]

I will try reaching the control unit via VAGCOM tonight and see if that wakes it up.

The unit has been soldered at all places by a electrician, still no go.

What is known is:
1. The unit only lights up the buttons, and the unit is _completely_ dead. No fan, not responding to anything. It's not just blacked out LCD it is _dead_.
2. The unit works perfectly in another car, and swapping units between cars it is always dead in mine but fully operational in the other.

Conclusion:
It should not be the unit itself but something in the car preventing it from starting.
It is really really annoying.

[k.alle]

Oh and thanks for the schematics and all info.

[UrS4boy]

What is known is:
1. The unit only lights up the buttons, and the unit is _completely_ dead. No fan, not responding to anything. It's not just blacked out LCD it is _dead_.
2. The unit works perfectly in another car, and swapping units between cars it is always dead in mine but fully operational in the other. Conclusion:
It should not be the unit itself but something in the car preventing it from starting.
It is really really annoying.

Okay, so your E87 CC head is fine. It is just not getting power to the E87 "brain". Have you checked Fuses S4 and S14?





E87 schematic image (partial) is from S2Central.net (5 pg B75 pdf)

[k.alle]

Okay, so your E87 CC head is fine. It is just not getting power to the E87 "brain". Have you checked Fuses S4 and S14?

Yes thats exactly it.
I've just been to the car and vagcom cannot find the controller. I have had access to it before (recently when it still was functional) and i can access engine, ABS and airbag controllers fine. Even though engine controller is a bit moody.

Excuse my ignorance but does fuses S4 and S14 in the schematics translate to No. 4 and no 14 in the fuse box?

[UrS4boy]

...Excuse my ignorance but does fuses S4 and S14 in the schematics translate to No. 4 and no 14 in the fuse box?

Yes.

S4 seems to come off the No. 30 constant power bus. It also feeds the "Y2" digital clock. The S14 seems to get its power through the "E1" Lighting switch (stalk) before going on to the E87 Climate control head.

[k.alle]

S4 & S14 just checked and seems OK.

So, could it be loose wiring in the lighting switch stalk?
Because come to think of it last time it came back to life it was right after I hit a big bump in the road with the car @ ~50mph.

I'm doing the 4 spoke airbag to 3 spoke airbag conversion, the last parts required arrives in a couple of days, so I could try to do some testing then.
I'm bad with diagrams (electrical), is there a specific pin at the stalk i could test while there?

[UrS4boy]

I'm bad with diagrams (electrical), is there a specific pin at the stalk i could test while there?

Here is the schematic of the E1 lighting switch. The only grey (gr) wire that corresponds to the "gr" wire in the Climate control Schematic (E1 to S14 to E87) is on pin "58" of the E1 (look for the grey wire). There is also a "J58" notation on the E87 diagram so it probably is the grey wire.

[audicoupe2.3]

http://www.s2forum.com/forum/showthread.php?p=727333#post727333

[k.alle]

Here is the schematic of the E1 lighting switch. The only grey (gr) wire that corresponds to the "gr" wire in the Climate control Schematic (E1 to S14 to E87) is on pin "58" of the E1 (look for the grey wire). There is also a "J58" notation on the E87 diagram so it probably is the grey wire.

I've done the conversion now and no change and couldn't see anything faulty, no multimeter yet!

But i've done some thinking, the 12v that is apparently missing causing it not to boot up should come from the ignition switch right?

The ac controller should start regardless of what state the lighting switch is in because that one is only responsible for illumination which is working as it should.
If i'm lost on this one please correct me.

So I'm tempted to give the controller a new feed with 12v where it gets its power from the ignition, just have to work out which pin to attack...

[k.alle]

Looking at schematics provided from audicoupe2.3 it seems that ignition switch feeds the outside temp display with 12v(?) through wire blk/blu and from there with wire gry/blu to the control unit to No.5 on the schematic.

PDF's i'm looking at.

http://www.s2forum.com/forum/attachment.php?attachmentid=42033&d=1370249985

http://www.s2forum.com/forum/attachment.php?attachmentid=42034&d=1370249985

[k.alle]

OK, so I might have found the problem, just need someone to confirm so that I don't mess things up.

I have just measured _every_ terminal behind the AC controller (wow was that tedious!).

I did all my readings using the A4 brown wire, earth.

When I arrived at D14 which is also brown I couldn't use it as earth connection, didn't get any readings through it.
D16 brown did work as earth connection btw, same size on the wires as well.

Can I just splice in a new earth at D14?
Is there any special routing I have to connect it or can I just connect It at a common earth somewhere in the car, it should not matter right?

Please tell me if I'm wrong here, any input appreciated!

[k.alle]

If i'm reading the schematics correctly here: http://www.s2central.net/S2_Schematics/B/B75.PDF , D14 comes up as earth right?
I'm to unexperienced with reading those so I can't be certain.

[Error404]

Yup D14 should be earth / ground

[johne]

D14 & D15 should both go to earth. You can join the wire on D14 to D15 as long as they go to a good earth on the chassis.

The "D" connector is the one all the power goes into the Climate Control Unit through.

A9 and A12 also go to earth which is the earth for all the signal/sensor wires.

John

[k.alle]

Well, it's a bit odd, D15 on my car is brown/anothercolor which has 11.82V on it using A4 as earth (small brown on mine).

D14 & D16 however are "thickish" fully brown wires, and I could use D16 perfectly as earth instead of A4 when testing.
D14 had no earth however so I hope the problem lies there.

I'll try putting D14 & D16 together and see if it boots up, If it does I'll make a new separate wire for D14 to a common earth point.

EDIT:
A9 = 11.2V & A12 = 11.4V, so they are not earth on mine.