Climate Control Unit Question

[LCOX]

I've posted 2 pictures. One is the climate control unit in a 1993 964.

The other is the fan booster amplifier(from what I've been told)

Can these units be repaired?

I'm having a problem with the amount of air that the fans output but only when the thermostat is in the warm/hot position. When it's in the cold position the fan speed works in all 4 positions with very strong output on high but when the thermostat knob is turned to the warm/hot postion the fan output is only about 50% as much. The fan still operates at position1 and 2 but when it's moved up to postions 3 and 4(high) the speed doesn't increase at all.

Is this a problem with the climate control unit or the amplifier?

Does anyone know?


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[ToreB]

You most probably have a defective (or two) mixer flap servos. If one or both of these fail to open when you set temp to hot, there will be problems getting enough air flow from the heat exhangers. You should also check your rear fan operation.
I highly suspect your front fan amplifier and CCU to be completely all right, but the answer to your question is: Yes, the CCU can certainly be repaired.

Have a look here for DIY fault finding, test procedures and fixes:
www.porschehvac.bergvill.com
Merry Christmas!
Tore

[911buff]

I have a similar but nonetheless different problem. My defroster works, right up till the rear fan kicks in...about 5 seconds. And when the temp knob is past 18 Celsius the controlled fan shuts down on all settings. As soon as the temp knob is brought back to 18 or below, it kicks back on. This happened after I had to replace the o-ring on the oil bridge below the rear fan. Everything is connected as it was before, so I am at loss. Maybe the cause of our problems are related. Any advise out there?

[ToreB]

911buff, you are describing a typical rear fan problem. My web pages linked in my previous post describes why, and how to mend it.
Cheers,
Tore

[28104]

FYI - I sent my CCU to Specialized ECU Repair with good results. Specialized ECU Repair, Replacement, & Testing - Restore or Exchange your Electronic Control Unit (ECU). Good luck resolving your issue.