B4 auto climate control into coupe

[johne]

I like this thread... I rediscovered my CC head unit in the dead project cave... From an LHD RS2 which I can recode for RHD

I have a notion that other CC head units might not be programmable for S2 application unless they have an option to ignore the compressor speed signal... Or you swap out the compressor to one that provides the signal but even then it might be off as the rpm wil not be in alignment with 5 pot. Except a CC unit that is compatible with AAN motor i.e C4 platform

Paul, I've tried 3 CC heads in my car and found them remarkably tolerant of missing sensors etc. so I suspect the missing speed sensor may not be a big deal. I don't have VAGcom to prove this or see if you can reprogramme. I've just got another ex A4 CC head from an ex US car. When I get the chance I'll plug it in & see if it throws up any errors.

John

[S2central.net]

Intersting... I suspect the CC unit will be raising an alarm but as long as it works perfectly then its no worries. There is a chance that some of the B5 head units can be coded for an engine type where there is no speed signal as per 5cyl on the euro B3/4 head units.

[Skull]

early b4 units do not have the speed sensor, probably the early c4 units too. and then the c4 units can be reprogrammed to the b4 specs...

ebay.de is your friend

[ShadowofBob]

What year C4's didn't have the speed sensor? I'd be interested in one since I can't control my heater valve with the B4 CC box. The C4 box I tried(don't remember the year) wouldn't bypass the speed sensor so it was useless.

[johne]

As I understand it no A4s i.e. '96 MY onwards had a coolant temperature sensor & the CCU uses time of engine running to calculate coolant temperature.

I'm not aware that any CCU was used to control a heater coolant flow valve as the coolant has to flow through the heater all the time to provide the thermostat bypass.

John

[Jamo]

I've still got all this to install have to get back on track!

[ShadowofBob]

As I understand it no A4s i.e. '96 MY onwards had a coolant temperature sensor & the CCU uses time of engine running to calculate coolant temperature.

I'm not aware that any CCU was used to control a heater coolant flow valve as the coolant has to flow through the heater all the time to provide the thermostat bypass.

John

Had a type there, meant to say speed sensor. The 90-91 Coupe GM auto climate units in USA have valve and so the the C4 cars. The B4 90's in the US do not have the valve.

[johne]

I got the sense from my A4 Bentley that only around model year '96 & '97 had the compressor speed sensor with CCU part number 8D0 820 043 H & J and only then if programmed since it talks about using VAGcom to reprogramme if you retrofit a (newer) replacement compressor without the speed sensor since two brands of compressor were used and only brand one had the sensor.

John

[ShadowofBob]

I don't know how it is in the UK, but in the US any car that had a serpentine belt system had a speed sensor compressor and any with V-belts did not. Also none of the serpentine belt compressors mount in the same place on the US spec cars. So only the v-belt non speed sensor compressors would fit in a Coupe or B3 90 chassis.

[S2central.net]

I am 90% sure that you can swap over the pulleys on the compressors to convert from serpentine to v-belt. I recall someone else posting having done this when they bought a 2nd hand compressor from AAN to put in RS2 only to discover the belt difference but swapping the pulleys was all that was required. Obviously the AAN sourced compressor wouldn't have had its speed sensor connected but its all good.

[Jamo]

Has anyone got the B5 A4 RHD aircon bentley schematics?

[johne]

I have

John

[Jamo]

I have

John

any chance you could email me it?

Just going through my stuff

My CCU is part number 8D0 820 043 H

The central box has the part number 8D2819031 on it

[Jamo]

Any pics of this installed without the front cover over the CCU unit?

Like to see how this installs into the S2 frame

[Skull]

jamo: you need a special bracket for the ecu unit. it is riveted on the plastic frame

p.s.: i drink beer, thanx