ABY type Digital airconditioner into early 3B

[Falco]

Hi guys,

So i've taken on the task to implement a newer type digital airconditioner into an older type 3B ('90//'91). We're sourcing the parts off of a B4 V6 and am having trouble to implement it into the existing wiring harness. Now these are the current flow diagrams i'm using:

- #54 Digital airconditioner 5- cylinder 162kW (3B early type) (because this system was in the car previously)
- #81 Digital airconditioner 6 Cylinder MPI ( the type i'm sourcing my parts off of.)
- #75 Digital airconditioner 5- cylinder 2.2 litre motronic 169 kW - S2 (ABY) (The system i should create IMO.)
Documents attached

There is a few ECU in and/or outputs i cannot really identify what their purpose is and how i should connect them to the older type ECU:

Page 75/2 shows that A2, on the climate control unit E87, is connected to pin 41 on the ECU wich is a signal to tell the ECU wether AC is on or off. To translate that to the 3B ECU that would either be pin 40 or 41 according to the motronic document found on S2central.com. can someone clarify?
That same A2 pin on E87 should connect to J155 (switch coolant pump turbocharger) wich I cannot find in the 3B wiring harness, does someone know where that should be located in the early 3B?

Also C12 on E87 connects to pin 6 on the ECU wich is used to switch A/C compressor off when full power is needed (comes back from throttle i suppose?). On the 3B ECU there is no such thing provided, am i allowed to just not connect C12 or ís there a pin i could connect this to?

Then there is pin A11 on the E87 that goes to ECU pin 46 (multifunction thermal switch) wich i can't find a pin for on the 3B ECU.

And some things I find hard to locate:
Drawing #75/4

• G106 in it, is that the ambient temp in the car or outside temp, in other word: is it located on E87 or in the instruments cluster?
• G62 Is not provided in the 6 cilinder parts car, what’s its function, can I skip it, if no where do I source it from?

I whole heap of questions I know, I’m hopin on someone who has done this before who can help me but of course any help is welcome.

Nederlands mag ook ?


Cheers,

Falco

[johne]

I suggest you read this:

https://www.s2forum.com/forum/techni...rol-into-coupe

and this:

https://www.s2forum.com/forum/techni...e-what-climate

Come back and ask more questions after that.

[Falco]

Thanks! Will do!

[Falco]

I suggest you read this:

https://www.s2forum.com/forum/techni...rol-into-coupe

and this:

https://www.s2forum.com/forum/techni...e-what-climate

Come back and ask more questions after that.

Hi John,

your document is very helpfull, thanks for sharing! However i'm still a bit in the dark for my ECU pins. By reading your pin out table i'm assuming you were fitting your AC to an ABY type motronic whereas i'm fitting it to a 3B. From the document found on S2 central i understand that there's a difference between ABY and 3B ECU's.

So specifacally: can you help me sort out where to connect CCU pins:

A2
C12
A11

To a 3B ECU?

Thanks in advance.

Falco

[rxl]

use google translate and look at this https://www.audidrivers.de/pdf/innen...limaanlage.pdf

[Falco]

use google translate and look at this https://www.audidrivers.de/pdf/innen...limaanlage.pdf

Danke schön! My German is acually not too bad, thanks

[rxl]

well then it wont be a problem

[johne]

[QUOTE=Falco;n2144028]

So specifacally: can you help me sort out where to connect CCU pins:

A2
C12
A11

To a 3B ECU?

[/QUOTE

Yes, I was fitting to an ABY Motronic.

Those three pins control the interaction between the ECU and the Climate unit, such as turning off the compressor if you're demanding maximum power or raising the idle speed if the compressor is engaged.

The 3B ECU is different to the ABY ECU and the only pin out for the 3B I could find is in Norwegian. The 3B ECU doesn't appear to support those features so just leave those pins unconnected. The Climate unit will work with no connection to them.

[Falco]

[QUOTE=johne;n2144097]

So specifacally: can you help me sort out where to connect CCU pins:

A2
C12
A11

To a 3B ECU?

[/QUOTE

Yes, I was fitting to an ABY Motronic.

Those three pins control the interaction between the ECU and the Climate unit, such as turning off the compressor if you're demanding maximum power or raising the idle speed if the compressor is engaged.

The 3B ECU is different to the ABY ECU and the only pin out for the 3B I could find is in Norwegian. The 3B ECU doesn't appear to support those features so just leave those pins unconnected. The Climate unit will work with no connection to them.

Ok that's great news, for your info i've found the 3B ECU pin out on S2central if thats any help to you. So if i understamd correctly the ECU, apart from disengaging compressor at full power, does nothing with the climate control and compressor, the system will be fully functional. What about rev increase when idling and compressor engage?

[johne]

Yes, I found the same sheets on S2central, those are the ones in Norwegian. The 3B doesn't appear to have an idle stabilisation valve. Idle speed must be regulated somehow but it may mean that if the AC compressor is engaged at idle the engine RPM will drop slightly. The compressor engage is a compressor disengage at full load so you just won't have that feature. None of these features are crucial, they are just "nice to haves" added for the ABY version and won't affect the climate operation significantly.