J255 Climatic Control Unit

[mattylondon]

Understandable Ray. Look after the pennies and the pounds will look after themselves. Let's hope you pick up a second J255 unit to investigate with. To note these do have component protection.

[tc4332]

Thanks for the heads up Matt.
I hadn't thought that CP would be involved, another silly expense if the unit is swapped out.
I was hoping that there would be a way of tapping in to the external wiring but of course with CAN BUS that is just wishful thinking. These cars are too technically complicated. Please bring back the days of just five basic circuits in cars.

[mattylondon]

Yeah CP is another expense you don't need. CAN BUS is great. It's the outdated clunky firmware that age these cars.

[tc4332]

Thanks to a very generous forum member I now have my hands on a J255.
VAG/Audi Number 4E0 820 043 A
SW 4E0 910 043 A 030

The unit was manufactured by Behr-Hella Thermocontrol GmbH (BHTC) in Lippstadt, Germany. This is not far from the Annual meet in Germany. I spent nine years in the area during my Army service and did know a lot of people there. Unfortunately the electronic guys thereabouts have moved on to a better place (this is the problem with age, everyone passes). I'm still in contact with their family members but none of them work for BHTC so no possibility of sneaking information through the old boys net.

Still can't find a circuit diagram but on close scrutiny I have found two small pads on the printed circuit board that I could solder two wires to. The plastic case has enough space for my remote receiver.
There are a number of openings in the case that two thin wires could pass through. I think this would be the better way to do this mod because the receiver aerial could be placed in a better reception area within the car.
I am a bit wimpish at the moment, it's cold outside, so I'll leave working on the car until later.

Big thanks to my secret donor.

[steamship]

These may be of use Ray, if you can read these things. PDF printer wouldn't print as one job.

[tc4332]

Thanks Sean.
The circuits that I was looking for are the internal ones for the unit.
I have now worked out where I can do this.
All I have to do now is pull my unit out, solder two wires onto the circuit board, refit the unit and connect the receiver to the two wires and test it.
Might have time on Saturday.

[Architex_mA8tey]

Here is Ray's excellent write up for his Webasto Heater Remote Control Retrofit!
Take a bow Ray and thanks for the detailed write up!