Climate into RHD avant

[Jamo]

I can send it yes, be handy as another member has a loom also looking to copy it.

What kind of timescales are you thinking here?

[S2central.net]

Dude you work far to quickly! I have all this kit for nearly 9 months or maybe longer now and haven't installed it

Right game on!

@Jamo - if you want to... could you send me that donor loom from an A4 so I can do some good detail on wiring 'how to' much like I did with the ABY conversions... so as to make it a little easier for folk to understand how to graft it into an S2 that already has manual aircon fitted.

I am looking for a loom locally to do this with, but no dice so far...

Upside for you will be having the guide completed in time for you along with a nicely labelled loom to make your conversion one step easier.

[S2central.net]

Just found a simpler way to hook up F118 from S2 manual system into the MY98 B5 system that avoids messing with wires under main fusebox...

F118 sits alongside F23 in the condensor housing... Working in that area do the following, whilst being careful NOT to cut any black/green wires -

1 - cut the sw/ge wire (black/yellow) that feeds into F118 - insulate the end coming from the loom and leave enough on the switch end to make a new splice.

2 - splice that sw/ge wire on F118 into the bl/ro wire that feeds into F23

3 - Then working back inside the car find the other side of F118 at T5g/4 on sw/gn - hook this into CCU loom at T10p/6 (goes to C2)


Cheers for now,

Paul

[S2central.net]

Whilst pins D16 & A2 have apparently the same function, i.e. they both go active to signify A/C on, I'm not convinced they have identical logic behind them and may not switch the same under all conditions. Moreover, if I were wanting to use the A/C on output to drive a fan relay I'd be using D16 as this is the one with the current drive behind it. Now as it happens, on the S2 it's the after-run relay that's used for the low speed fan when the A/C is on and this is an electronic relay so the current draw may well be very low and either D16 or A2 would do, but I'd still opt for D16 as it's the current drive one and where the fan relay is connected by Audi.

May also be that one output is active high and the other active low but I haven't checked that.

John

Agreed there mostly John... D16 is the proper way to engage speed 1 - it is generic to all engine types. D16 is an 'active low' output as far as I can tell - it is a switched path to 0V.

On the S2 installation however, the afterrun relay does the same job by way of CCU --> ECU signalling from CCU pin A2, so strictly speaking you don't really need D16 wired up to make it work.

That said - I agree that using D16 is superior as it gives a belt and braces approach such that a failure of afterrun relay may otherwise prevent the fan being activated when climate is turned on.

[S2central.net]

Paul, not sure I'm with you here but you must retain the logic of F73. F73 is probably the most critical component in the A/C system, manual or climate and certainly isn't deleted in the climate system. Power is fed to the compressor clutch N25 by relay J44 in your description and J44 is fed by F73. The signal feed to J44 comes from D8 on the climate CCU and the state of F73 is monitored by pin C3 on the CCU.

Together, this gives a logical AND system so that there has to be gas in the system AND the CCU wants to demand A/C compressor on AND the system hasn't been on so much that the pressure in the system has dropped too low so the evaporator freezes up. F73 is the logic element for the CCU.

John

John - agreed on importance of F73. It does exist on B3/B4 climate system... and also on the MY96 system on the B5 but it was deleted for MY97 - at least going by US Bentley diagrams. It does not appear on the UK diagram for MY98 either.

In short, I would retain F73 when converting to climate regardless of what year the head unit was sourced - pretty easy to do by using B75 schematics as a reference.

[johne]

Sheet 5 is pretty much exclusive to donor climate loom with the exception of two pins for ECU signalling...

A2 is a sw/ge wire on T10/6 - a brown blug if you have it on the donor loom - connect this to T5h/2 on the S2 (or T10e/2) where it should land on pin 41 of the ECU and pin 3 of the afterrun relay to signal that aircon is turned on... This in turn is used by afterrun relay on the manual system to turn on the fan to speed #1... Looking at S2 climate loom it is curious that CCU pin D16 is also used for this function so you can wire that up to terminal K4 in the S2 fusebox if you wish. Bit of an odd one that... makes me want to buzz that out on the S2 to be sure

Whilst pins D16 & A2 have apparently the same function, i.e. they both go active to signify A/C on, I'm not convinced they have identical logic behind them and may not switch the same under all conditions. Moreover, if I were wanting to use the A/C on output to drive a fan relay I'd be using D16 as this is the one with the current drive behind it. Now as it happens, on the S2 it's the after-run relay that's used for the low speed fan when the A/C is on and this is an electronic relay so the current draw may well be very low and either D16 or A2 would do, but I'd still opt for D16 as it's the current drive one and where the fan relay is connected by Audi.

May also be that one output is active high and the other active low but I haven't checked that.

John

[johne]

Oh just one last thing... you could retain use of F73 logic by splicing it in series with sw/bl feed into J44... low system pressue (no gas) will prevent the compressor relay from being activated... CCU must have some other logic to do this but it's an option.

The switched side of F73 supplies power to manual system on S2 via a sw/gr wire which you can find at T8a/2 before it makes its way into Aux position 4 on pin 11 of that relay block. Personally I would use it cos its there... probably deleted on the climate cars to save a buck.

Paul, not sure I'm with you here but you must retain the logic of F73. F73 is probably the most critical component in the A/C system, manual or climate and certainly isn't deleted in the climate system. Power is fed to the compressor clutch N25 by relay J44 in your description and J44 is fed by F73. The signal feed to J44 comes from D8 on the climate CCU and the state of F73 is monitored by pin C3 on the CCU.

Together, this gives a logical AND system so that there has to be gas in the system AND the CCU wants to demand A/C compressor on AND the system hasn't been on so much that the pressure in the system has dropped too low so the evaporator freezes up. F73 is the logic element for the CCU.

John

[S2central.net]

Oh just one last thing... you could retain use of F73 logic by splicing it in series with sw/bl feed into J44... low system pressue (no gas) will prevent the compressor relay from being activated... CCU must have some other logic to do this but it's an option.

The switched side of F73 supplies power to manual system on S2 via a sw/gr wire which you can find at T8a/2 before it makes its way into Aux position 4 on pin 11 of that relay block. Personally I would use it cos its there... probably deleted on the climate cars to save a buck.

[S2central.net]

On Sheet 6, to close things out it is only J44 that we are concerned about. You should have the relay block on the donor loom - I dunno if this fits directly into S2 carrier - its no big deal really but the donor loom will look after connectivity to terminals 30, 85 & 86 on that relay - tracks 56, 57 on the B5 schematic.

All you need to do is wire up N25 by linking the gn/ge wire on donor loom T10p/1 to the S2 at T5g/3 (a green plug in the auxiliary carrier) - the wire should also be gn/ge on the S2.

And that's it for now...

[S2central.net]

Sheet 5 is pretty much exclusive to donor climate loom with the exception of two pins for ECU signalling...

A2 is a sw/ge wire on T10/6 - a brown blug if you have it on the donor loom - connect this to T5h/2 on the S2 (or T10e/2) where it should land on pin 41 of the ECU and pin 3 of the afterrun relay to signal that aircon is turned on... This in turn is used by afterrun relay on the manual system to turn on the fan to speed #1... Looking at S2 climate loom it is curious that CCU pin D16 is also used for this function so you can wire that up to terminal K4 in the S2 fusebox if you wish. Bit of an odd one that... makes me want to buzz that out on the S2 to be 100% sure.

C12 is the sw/gr wire on donor plug T10/8 - connect this to T5h/1 on the S2 where it extends to the ECU on pin 6.

[S2central.net]

Only other thing of note on Sheet 4 is pin B1 which should connect to your ambient temp display - achieved via T10e/10 on the S2 loom on a br/ge wire

[S2central.net]

Sheet 4 then and the mysterious F129... The normally closed section of this switch is F118 in old money - shown as br/bl and br/ws on Track 25.

F118 is already on your car and it just needs spliced into the B5 loom as follows.

1 - At the S2 fusebox you need to find the sw/ge wire on Track 17 (B76/2) and DISCONNECT it from A85k

2 - Take that sw/ge wire and attach it to T10p/10 as shown on Track 25 of the B5 sheet - should be a sw/bl wire

3 - Then find the sw/gn wire at T5g/4 on the S2 - this is the other side of F118 - connect it to B5 plug T10p/6 where it meets the br/bl wire into C2


While talking about this T10p plug... the tidiest way to do this is with a matching plug - if you send me part number of plug on the B5 loom I can source t'other side and matching pins... or you can simply chop off Audi plug and use aftermarket male/female multipin jobbies

[S2central.net]

Oh before we finish Sheet 3 - Pins D14 and D15 will have big dirty obvious earth straps - thats an easy one....

[S2central.net]

One last thing on Sheet 3 - Track 21 and pin D16... this is used on the B5 for fan control... when climate switched on, this goes to 0V and activates speed 1... because the wiring logic for fans is different we can ignore this one as the S2 curiously uses signalling to ECU and afterrun pump so as to run the fan when aircon switched on. Hold that thought, but ignore pin D16 - Do not fit.

While we are here - one important plug on the donor B5 loom is T10p - supposedly a grey 10 pin block at or near the fusebox - this is a number of pins that will be convenient to graft into the S2.

[S2central.net]

Now lets look at Sheet 3 on the B5 diagram... There are a few wires here that are of note for the conversion into S2...

Track 14 - that sw/bl wire will go to the fusebox for X-contact... use terminal J75al on the S2 fusebox for this (as per B75/4 Track 51)... This will use the B5 ACC loom to extend the X-contact to numerous other parts of the loom (V2, F118 and J44)

Track 15 - that sw/ro wire will go to the fusebox for switched 12V (T15)... you could use J75al again actually for convenience, but if you already have it wired to another fused & switched feed then OK... only thing is it needs to be 30A fuse as this one is for blower motor - so J75al is good as you should see 30A fuse in position S17 already.

I think you already have the blower wired up... the B5 climate system will be wired to a 5 or 6-pin block at J126 via pins C11, C14, C16 and 0V... I think there is a 2-pin extension from this to the existing blower motor (V2) in the S2 evaporator housing.