Climate Control Question
10-15-2006, 01:58 PM
#1
Three Wheelin'
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Climate Control Question
The weather is getting a bit colder here and I am driving my Porsche more often now that my idle stability issues are pretty much fixed. 
(Thanks Jason!) 
I was driving home last night and turned on the heat for the first time in recent memory. As I recall... In the summer time when I use the fan settings while using the A/C the power (fan speed) is stepped by the numbers and you can hear and feel the difference when you turn the dial to the next number setting. However... When using the heater last night I noticed that the fan barely changed until I turned it to full blast (setting 4). Likewise... The heater needed to be turned to almost the full hot position before I received any heat. So... Now the heat comes on and then I noticed that the fan speed reduces a little. When I turned the heat from full hot down just a little... I hear the fan speed increase again. 
I would assume that this is connected to the code that was picked up by my new diagnostic interface. (code 45 - Inside Sensor Blower Motor) My question is... How do I fix this? What do I need to take out and clean or replace?
(Thanks Jason!) I was driving home last night and turned on the heat for the first time in recent memory. As I recall... In the summer time when I use the fan settings while using the A/C the power (fan speed) is stepped by the numbers and you can hear and feel the difference when you turn the dial to the next number setting. However... When using the heater last night I noticed that the fan barely changed until I turned it to full blast (setting 4). Likewise... The heater needed to be turned to almost the full hot position before I received any heat. So... Now the heat comes on and then I noticed that the fan speed reduces a little. When I turned the heat from full hot down just a little... I hear the fan speed increase again. I would assume that this is connected to the code that was picked up by my new diagnostic interface. (code 45 - Inside Sensor Blower Motor) My question is... How do I fix this? What do I need to take out and clean or replace?
10-15-2006, 03:07 PM
#2
"I would assume that this is connected to the code that was picked up by my new diagnostic interface. (code 45 - Inside Sensor Blower Motor) "
Not necessarily! You need to check:
1. That all the servo motors, e.g. mixing flaps, are working properly.
2. That the blower motor controller is working properly.
3. That blower motor current sense resistors are O.K.
Remember, faults codes are ONLY a guide to troubleshooting and NOT the "absolute end all".
To fully diagnose the CCU system, you need to be able "drive" , i.e. not only read fault codes,
all the climate control elements, e.g. servos & blowers, via a tester, e.g. Hammer/PST2.
Not necessarily! You need to check:
1. That all the servo motors, e.g. mixing flaps, are working properly.
2. That the blower motor controller is working properly.
3. That blower motor current sense resistors are O.K.
Remember, faults codes are ONLY a guide to troubleshooting and NOT the "absolute end all".
To fully diagnose the CCU system, you need to be able "drive" , i.e. not only read fault codes,
all the climate control elements, e.g. servos & blowers, via a tester, e.g. Hammer/PST2.
10-15-2006, 06:06 PM
#3
Three Wheelin'
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Thanks for the reply...
1. The mixing flaps appear to be working properly. I've tried all the combinations and the air goes where it is supposed to.
2. Where/how do I check the blower motor controller?
3. How do I check that the blower motor current sense resistors ar good?
I'm thinking it may be wise to go ahead and replace the following;
A. Series Resistor for Engine Compartment Blower Motor
B. Temperature Sensor (in Blower Duct) for Engine Compartment Blower Motor
The cost would be $52.75 for both via Pelican Parts. I took the series resistor out of the blower tube and it looked fine to me. There is no reading to take on this it would seem... Other than no resistance at all. The built-in relay looked fine. I'm not sure what the temp sensor is supposed to look like... It is a sealed unit and I'm not sure how to test it.
Any other help would be greatly appreciated.
Rick
1. The mixing flaps appear to be working properly. I've tried all the combinations and the air goes where it is supposed to.
2. Where/how do I check the blower motor controller?
3. How do I check that the blower motor current sense resistors ar good?
I'm thinking it may be wise to go ahead and replace the following;
A. Series Resistor for Engine Compartment Blower Motor
B. Temperature Sensor (in Blower Duct) for Engine Compartment Blower Motor
The cost would be $52.75 for both via Pelican Parts. I took the series resistor out of the blower tube and it looked fine to me. There is no reading to take on this it would seem... Other than no resistance at all. The built-in relay looked fine. I'm not sure what the temp sensor is supposed to look like... It is a sealed unit and I'm not sure how to test it.
Any other help would be greatly appreciated.
Rick
