Wiring questions - B5 1.8T Quattro '99 Model

[Grant620]

Hi Guys,
I'm doing some wiring on my '99 Audi A4 1.8T Sport Quattro Avant and I'm drawing some blanks on some ECU pins...
Can anybody help?
Basically - do you know what these pins actually do?
Pin 8 - Black / Grey wire -
Pin 18 - Brown/White wire - Goes to Multifuntion display, but what does it do?
Pin 19 - Green/Black - Is this the OBD port pin 6?

Is there a wire that goes from the ECU to the "Check Engine" light?

Thanks in advance!

[Crasher]

Presumably this is engine ECU wiring on an AEB?

Pin 8 black/grey goes to the brown plug in the ECU box at pin 8 and is the load signal to the A/C system and auto box if fitted.

Pin 18 should be yellow, goes to pin 3 of the brown plug and is for the auto check and again, auto box

Pin 19 goes to the yellow plug at pin 2 and goes to the dash green plug at pin 5 and is the "W" wire for the charging circuit.

[Grant620]

Thank you. AJL Engine ECU yes...

Presumably this is engine ECU wiring on an AEB?

Pin 8 black/grey goes to the brown plug in the ECU box at pin 8 and is the load signal to the A/C system and auto box if fitted.

So basically just to tell the ECU that the aircon is on?



Pin 18 should be yellow, goes to pin 3 of the brown plug and is for the auto check and again, auto box

So of no importance on a manual car? Does it light up the transmission light on the display?



Pin 19 goes to the yellow plug at pin 2 and goes to the dash green plug at pin 5 and is the "W" wire for the charging circuit.
Sorry for stupid question, but what does this do?