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I'm having issues with my CCU. The CCU fan never shuts off even after the ignition is off (draining the battery) and my fan control is all or nothing, no matter the setting. Can someone recommend someone to repair or rebuild the CCU?
Tore did mine also after BS'ing around with some crowd in TN that made a pigs ear of the whole thing. Loren in CA is also a recommended option. Avoid the 'services' for repair on Ebay.
I have already. narrowed it down to that will be sending the unit to Tore over the winter and fixing some sensors ans servos that are not working properly.
We however completely upgrade the CCU. Specifically we desgined the new hardware to completly avoid battery drains in the car, and tune the fan for better airflow in the car, along with many other cool things.
A working CCU will not drain the battery.
The unit is designed to stay on for several minutes after ignition off to maintain a reliable measurement of the cabin temperature on short stops.
In addition, the CCU measures engine temperature and will run the rear fan in cooling mode if needed during this period to reduce engine temperature at standstill.
I see no reason to upgrade or change the unit to avoid this.
A working CCU will not drain the battery.
The unit is designed to stay on for several minutes after ignition off to maintain a reliable measurement of the cabin temperature on short stops.
In addition, the CCU measures engine temperature and will run the rear fan in cooling mode if needed during this period to reduce engine temperature at standstill.
I see no reason to upgrade or change the unit to avoid this.
We however completely upgrade the CCU. Specifically we desgined the new hardware to completly avoid battery drains in the car, and tune the fan for better airflow in the car, along with many other cool things.
^^
That right there is some great (but misguided) marketing BS...
You've linearized the fan speed control, and claim that your CCU provides "better airflow". The maximum fan speed has not changed at all. For any given setting of the control **** on your modified CCU unit, there is a corresponding (but different) setting on the original CCU that results in the same airflow. It is not as if the fan speed control setting is limited to the 4-positions, the speed control is continuous over the entire range.
Did you ever stop to consider that the designers may have intended for the speed control to be non-linear? The non-linear control makes it easier to dial-in the desired fan-speed once the cabin has reached a comfortable temperature and you no longer need something approaching full-blast.
See this before and after illustration of how the fan speed works on the original CCU design:
The 1,2,3, and 4 speeds did not come "out-of-the-box" working as one would expect.
We felt like that needed to be fixed.
While we were at it we noticed that we could increase the voltage sent to the fans, and therefore they would push more air through the cabin. It's that simple.
This is a DEMO of another flaw that needed fixing ASAP:
You missed the point. The fan control was intended to be a logarithmic function, like the volume control on a radio. That is not a flaw, that is a smart design choice. You converted the logarithmic control function to a linear function, which makes it more difficult to make small incremental adjustments of the fan speed.
Ivan,
Thanks for bringing this point up.
The 1,2,3, and 4 speeds did not come "out-of-the-box" working as one would expect.
We felt like that needed to be fixed.
While we were at it we noticed that we could increase the voltage sent to the fans, and therefore they would push more air through the cabin. It's that simple.
This is a DEMO of another flaw that needed fixing ASAP:
This is misleading and incorrect.
First of all, you are demonstrating changes that were made by Porsche themselves during the usage years of this unit. The non-linear behaviour of the blower motors was optimized to give the best experience of air flow regulation, especially when introducing the vacuum controlled resirc flap in the 993. Four major software versions were introduced during the 964/993 production period. By the way, the fan speed is not limited to four steps, there is over 30 steps in the PWM fan speed signal from zero to full speed.
Secondly, you are demonstrating a feature of the Climate Control Unit, not a flaw. You turn the temp **** up to show that the main blowers shut off.
A missing rear fan feedback will make the unit to turn off the front blowers. This is a feature built into all versions of the CCUs. I have reason to believe that this is a security feature. It enables the user to discover that there is a problem with the rear fan, but I guess this was implemented to avoid excessive currents in a seized fan. This was further enhanced when the updated thermoswitch rear fan resistor was introduced after fire incidents. Removing this safety feature will mask any rear fan faults, which by the way is very often seen.
Third, it is not possible to increase the voltage to the fans. Applying more than 12V to the fan motors will destroy the motors. The front blowers are PWM regulated, and max fan speed is when the pulse is always on. (12V directly to the fan motors)
In fact, the PWM signal at full speed has a small notch or off-period, due to a limitation of the hardware (microprocessor) used in the CCU. However, at this PWM frequency, and given the nature of running fan motors, the millisecond off period is not relevant. Changing the regulation non-linearity could at best be described as "increasing the voltage" at a give speed setting, but the same is the case if you adjust the speed fan ****.
Finally, your marketing material indicates that you are using the latest 993 CCU software version in 964 CCUs. This is problematic and needs careful attention. The unit will report the wrong part number in OBD diagnosis, and many features would have to disabled or changed to make the unit work prperly. Examples are the missing fan feedbacks, rear air selector valve, outside temp sensor. I hope you have found out how any disabling of such features affects the temp regulation mechanism.
I always recommend to use a CCU version that is made for the vehicle type.
09-12-2017, 11:40 AM
CCU Rebuild Recommendation
