B4 auto climate control into coupe

[rj scotty]

I can't believe this might actually work

Keep up the research guys

I can see my dashboard coming out soon

cheers

rich

[S2central.net]

It will work - Johne did it the hard way with a home-made loom... My intent is to document it all such that its easier for others to do this with existing parts such that it will be extremely close to the factory fitted climate system on the LHD cars.

Oh and along the way, hope to impart a fair bit of knowledge and fault-finding info amassed on the various a/c systems we have here. I've been promising that for years now.

Paul

[princepolo]

wow, great job. I know one guy in Poland who went thru this thig too.
What I remember he said he's had 2 cars in garage while working on it. The one with manual and one with climatronic. It took him a while.

[S2central.net]

Its still a BIG job for sure...

When you say 'climatronic' - I assume you mean the old style climate control that had lots of vacuum pipes ? Or do you mean what I call the '1st generation climate control' system as fitted from 1992 onwards to Audi B3/B4 (LHD only), early C4 and early B5 cars ?

[princepolo]

What we use to call :climatronic: is the units what b out to his Coupe - the A/C head which you can control by buttons (c4 units)

I know 3 kinds of early climat control units:
1 - three regular wheels with two buttons below (in b3/b4) or on left side (in c4)
2 - "old style climatronic" with red symbols on black electronic display, with red buttons (in 100/200 and others)
3 - "climatronic" - typ. A/C head unit what ShadowofBob installed in his coupe.

It was 5 years ago so the only thing I remember my friend had no. 1 and installed the no.3 in his coupe. And that was a pain in the *****. He had both cars in the garage and was swaping parts from one to the other one.

[ShadowofBob]

Just wanted to update to say that I was able to flash the climate head to 00051 (5 for 5cyl and 1 for diesel w/o speed sensor, 2 is gas, but checks for sensor) with a hong kong VAG-COM cable. Just had to add a K connector to the K line from the climate unit and add it next to the other 2 pin diagnostic connectors. Was also able to clear all codes on the control unit stored from it's previous life/installation in a V6. Now all I need is some warm weather and to charge the AC system so I can test it.

Great info on the RHD swap. Looks really interesting.

[S2central.net]

Are you sure about that coding - What is part number on your head-unit ?

I thought you used the head-unit from a LHD V6 80/90 which should be 8A0-820-043. Looking at factory info here the code I have for 5-cyl are as follows -

050 - Petrol LHD
051 - Petrol RHD
052 - Petrol USA

Selecting 5-cyl is what should make that head-unit ignore the speed sensor AFAIK.

Note these codes do NOT apply to the head-unit from B5, C4 or other variants. I want to be absolutely clear on that.

[ShadowofBob]

Yeah, my head is from a USA LHD V6 90. I asked SCarGo02 what the codes were since he recoded the unit on his 90 a while back when he had a bad speed sensor and that is what he told me. He said it still looked for the speed sensor with 052. I think that's because the 5 cyls in the US with that control unit were the UrS4's which always had speed sensors. That makes sense if your coding is correct though. Where did you find your coding info from? Any differences between 050 and 051?

Part number for my climate unit according to VAG-COM is 8A0-820-043 F

[SCarGo02]

Are you sure about that coding - What is part number on your head-unit ?

I thought you used the head-unit from a LHD V6 80/90 which should be 8A0-820-043. Looking at factory info here the code I have for 5-cyl are as follows -

050 - Petrol LHD
051 - Petrol RHD
052 - Petrol USA

Selecting 5-cyl is what should make that head-unit ignore the speed sensor AFAIK.

Note these codes do NOT apply to the head-unit from B5, C4 or other variants. I want to be absolutely clear on that.

The Bentley Manuals for B4/C4 US cars states that the last digit is for gasolione engines (as we didn't have any non-gasoline powered cars here one would assume that a different number would dictate a different type of fuel engine. For instance, our B4/C4s all came with the 12V V6, so they were coded to 00062, 5-cylinder S4/S6s were coded to 00052.

When I was having problems with the AC in my '94 90 changing the 2 to a 1 made the climate control unit not look for a clutch speed sensor and/or report a clutch speed sensor error code.

Bob changed the code to a 5-cylinder because he swapped the climate control system into his 7A/20V B3 CQ. It originally came from a 6-cylinder B4 sedan.

[S2central.net]

That Bentley info is only part of the story... And the coding is different between the B4, C4 and B5 head-units. Here's everything on the B4 codes I have... AFAIK none of the 5-cyl engines have the speed sensor.

1st digit is always zero

2nd digit is number of cylinders

3rd digit defines engine type AND territory
0 LHD, Petrol
1 RHD, Petrol
2 USA, Petrol
3 LHD, TDI
4 RHD, TDI
5 USA, TDI
6 LHD, SC-TD
7 RHD, SC-TD
8 USA, SC-TD

SC-TD being a swirl chamber turbo diesel

It used to confuse me greatly why the head unit needed to know LHD vs RHD but its because the fresh air flap position motor (V71) only applies to LHD models

I can't think why there is special designation for USA on the head-unit though. Only odd thing with that territory is that it is the only LHD region where speed is in mph instead of kph but I can't see why the a/c would care - it gets VSS from the speedo in a generic format AFAIK.

I can post up my other info on B5 and C4 head-unit codes if you wish... They are very different.

[S2central.net]

Oh my source of info is the OFRM for the Audi 80 1992 onwards HVAC chapter.

And I have OFRM in form of Auntie Elsie ;-) for the B5 and C4

If you have the B4 head-unit then you want it coded as 052 - the 2 denotes it as USA Petrol !

[ShadowofBob]

Interesting list. How do you differentiate if there needs to be a compressor speed sensor? Pretty sure 052 will want to look for one.

[S2central.net]

I don't agree - I think 050 or 052 is what you need on that app.

Going to 06x tells it to expect a speed sensor...

Unless the USA 5-cyl engines (052) where shipped with a compressor that does have the speed signal - that would be weird especially as I thought the last 5-cyls to get to the USA on the B3/B4 family were the 20VCQ which wouldn't have this aircon.

Paul

[ShadowofBob]

Went with 050. The last 20Vs in the USA and only ones to get the climatronic system were the UrS4/S6 and those all had speed sensors on the compressors.

[ShadowofBob]

Just an update on this. I have fully working AC now after switching to an Audi 90 AC relay rather than the one that was included with the Coupe.

So the whole swap is a success and fully functional. I'll be finalizing the How-To in the next few days with the updated information.