Climate into RHD avant

[S2central.net]

So I say again - do not trust the russki dagrams... they are close but not perfect.

[rj scotty]

beat me to it
still strange no 12v permenant

[S2central.net]

I am looking at My97 and 98 diagrams right now - there is no permanent 12V supplied to the head unit.

I've captured some tables of info here - saad man that I am about wiring... will endeavour to formalise it and compare / contrast the two systems.

[S2central.net]

Guess the later head unit relies on NV memory for whatever it has to store and doesn't require the permanent 12V feed

[rj scotty]

no it's switched

[S2central.net]

C13 exists as unswitched 12V (terminal 30) on the MY96 A4 schematic

But it does not feature for MY97 or MY98 - instead the supply is a switched feed on a black/red wire that lands on pin D9 of the head unit.

Pin D9 on the MY96 wiring has a completely different purpose with a connection to F73 (refridgerant low pressure switch on the evaporator) so be careful like I said to ensure everything lines up.

[rj scotty]

looking at the diagram again now

Could it be D9 on this controller is a permanent 12v feed ?

cheers

rich

[johne]

Sun light sensor is intact

I defiantly do not have C13 to space in the connector is empty

I have left the ccu off for a long period of time with some random settings and appearers to retain them, it seems strange to me that there is no permanent 12V.

I can understand that it can remember last settings without power using modern flash memory but not how it could calculate engine standing time without power.

John

[rj scotty]

Sun light sensor is intact

I defiantly do not have C13 the space in the connector is empty

I have left the ccu off for a long period of time with some random settings and appearers to retain them, it seems strange to me that there is no permanent 12V.

[johne]

Here is an odd ball then, my fan multi plug has 3 wires

Running through the pin compatibility list of this ccu against the list in johne's guide
The only pins that differ as far as I can tell are:

D6: vac recirc no function
C14: wired to 5 wire fan control which I don't have, ill assume jonhe's chart is correct
calling it +12V X Load dump (what dose this mean ?)
B13: goes to J218 on A4
A6: Unknown posibbly goes to J218 on A4
I don't have C13 permanent suplly looks like this ccu don't need it

Remember all my actuator wires and and sensor wires are intact

Connections I need to make are IE I have bare ends:

A1 Diagnostic K line
A2 A/C on status
A8 Outside air temp
A11 High temp cut (unsure on this as it goes to J218 on A4)
C2 High pressure switch monitor
C3 Low pressure switch (I have the relay)
C4 Vehicle speed (unsure on this as it goes to J218 on A4)
C6 RPM (unsure on this as it goes to J218 on A4)
C7 Light switch
C12 Full throttle inhibit (only used on certain engine model A4)
C14 +12V X load dump
D6 (missing on this controller) 12V to vac recirc flap a toggle switch will do for now.
D8 Compressor relay drive
D9 +12V x load dump
D14 Ground
D15 Ground
D16 Rad speed 1 drive

Plus the common conections (except C13)

Not so bad when you look at it like that

cheers

rich

I'm surprised D6 doesn't work for the vac recirc solenoid as it does on my A4 sourced ECU - it may be solved by a VAGcom software change.
A6 & B13 - I don't know what they do. I do have all the A4 wiring diagrams on a Bently CD but I never studied in detail the ones for the post '96 model year but I don't believe that there was anything like a 30% wiring change each year.
C13 - the permanent +12volt supply. I haven't tried to run my system without this but I assume it's needed since the A4 ECU doesn't have an engine temperature sensor which the A80s did and calculates engine temperature from how long the engine has been running - and how long it's been stopped up to 2 hours at which point it assumes it's cold. To do this and to remember the last settings I assumed the ECU would need a permanent +12 volt supply.

The tables in my guide list suggestions as to where you can connect the wires you've listed with bare ends.

C12 is a bit like A6, it's there to cut off the A/C compressor if you're demanding maximum power, i.e. pedal to the metal, but you don't have to connect it if you don't want to.

You haven't mentioned the sunlight sensor but I guess that's part of the loom you removed from the A4 donor car.

John

[johne]

Thanks mate

Now what dose 12v x load dump mean, I bet I feel stupid when you tell me

cheers

rich

+12 volts is fed into our car electrics in 3 ways.

The "30" supply which is direct from the battery and always on.
The "15" supply which is fed via the ignition switch so is only on when the car is running, ie you've turned the key one clic.
The "X" supply, sometimes called the load dump supply because it is the same as the "15" supply but is cut whilst you are actually cranking the engine. Lots of electrics on whilst the engine is running are fed via the "X" supply so they are momentarily disconnected whilst the engine is cranked to ensure maximum battery power to starting the car.

If you look across any of the Audi wiring diagrams on S2Central you'll see every diagram has a line across the top labeled 30, 15, X & 31.

John

[johne]

My blower drive output is on pin C16 as johne's list not tthe above diagram
But my fan speed monitor is on C11

Which is the same as in my guide and on my car so would be correct for a 3 wire heater fan motor speed controller.

John

[rj scotty]

Thanks mate

Now what dose 12v x load dump mean, I bet I feel stupid when you tell me

cheers

rich

[johne]

Just looked at the 1997 diagram and compared them to johne's. They appear to be the same in all aspects except pin A11 this goes to the instrument cluster in the A4 where as johne took it to T5h pin 4. I'm struggling with the blower wiring at the minute. it appears from the diagram that the live supply to the blower is cut when the low pressure relay is denergized, so if your a/c lost gas your blower would not work

Also my loom dose not have a C13 live supply could be nothing, could be a headache

cheers

rich

A11 is the input to the CCU to tell it that the engine is overheating. In response it cuts off the A/C compressor. The ECU gets the same signal and in response curtails boost. The signal comes from the MFTS but in order to pick it up inside the car you can choose the ECU connector itself or T5h.
The wire may indeed have come from the dash in the A4 - where it illuminated an "overheating" lamp perhaps but not relevant to fitting in our cars.
If you're not worried about having that protection in the case of overheating, it's a wire you can leave unconnected.

John

[rj scotty]

Here is an odd ball then, my fan multi plug has 3 wires

Running through the pin compatibility list of this ccu against the list in johne's guide
The only pins that differ as far as I can tell are:

D6: vac recirc no function
C14: wired to 5 wire fan control which I don't have, ill assume jonhe's chart is correct
calling it +12V X Load dump (what dose this mean ?)
B13: goes to J218 on A4
A6: Unknown posibbly goes to J218 on A4
I don't have C13 permanent suplly looks like this ccu don't need it

Remember all my actuator wires and and sensor wires are intact

Connections I need to make are IE I have bare ends:

A1 Diagnostic K line
A2 A/C on status
A8 Outside air temp
A11 High temp cut (unsure on this as it goes to J218 on A4)
C2 High pressure switch monitor
C3 Low pressure switch (I have the relay)
C4 Vehicle speed (unsure on this as it goes to J218 on A4)
C6 RPM (unsure on this as it goes to J218 on A4)
C7 Light switch
C12 Full throttle inhibit (only used on certain engine model A4)
C14 +12V X load dump
D6 (missing on this controller) 12V to vac recirc flap a toggle switch will do for now.
D8 Compressor relay drive
D9 +12V x load dump
D14 Ground
D15 Ground
D16 Rad speed 1 drive

Plus the common conections (except C13)

Not so bad when you look at it like that

cheers

rich