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from tech: If you could find a compatible unit to confirm that would definitely tell you if its the Climate controller or something else, but wiring and the actuators are the only other things that could be at fault, possibly a faulty ground strap, which we have seen before.
You could have multiple problems in your car, causing this behaviour.
However, you have a 993 CCU, and this needs several rewiring actions in order to work properly in a 964. The actual rewiring depends on the 993 CCU version.
As an example, unless rewired, the oscillating behaviour of your condenser fan (without A/C on) is caused by the CCU trying to activate the rear air selector valve. This is a feature that was introduced in the 993, and this CCU output is actually connected to the condenser fan high speed in your car.
There is also risk of internal CCU damage depending on which CCU version you are using. I would advice to disconnect the CCU until you have sorted all rewiring problems, or reverted to a 946 CCU.
Cheers,
Tore
Thank you for the info. Unfortunately, I do not know what the numbers for this unit are as it appears the sticker is gone. I recall a few years back, the mechanic had swapped out my original unit for this one because he said it wasn't working. I only had one A/C button and now I have two. Is there any way to find out which mine is?
The part number is unfortunately not printed elsewhere. You can use a Porsche-compatible OBD diagnostic tool to read out the part number.
Installing this unit in your car without modifications of the wiring is a mistake. If possible, I would advise to try to get hold of the original unit and have this checked/repaired.
Depending on which unit version your car had originally, there is no real advantage to use the 993 unit, except for the added A/C max shortcut button. The high fan speed/minimum temperature shortcut setting can be done manually anyway.
An alternative would be to identify the part you have now, and make a list of necessary wiring modifications. There's 4-6 mods necessary, depending on unit version.
Cheers,
Tore
ToreB! You are da man! Your recommendations got my 993 CCU working again! I now have HEAT and my passenger and I can stay warm on our fun adventure in my 964!
02-14-2019, 06:14 PM
964 L & R servos doing the Cha-Cha!
Needs looking at, and when further up the priority stack of 964 to-do's it'll be on it's way to Tore to fix up - yey..
