HVAC Blower (Only) Acting Erratically
#1
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I was just about home when I began to have an issue with the cabin HVAC blower/fan unit.
After some investigation I have narrowed down to the blower speed not responding to the CCU (Climate Control Unit).
Here are my symptoms: A/C compressor (on/off) and temp responds to the selected variables. All baffles function and direct air where selected. The issue issue I am having is I cannot control fan speed and if I turn off the climate control unit as a whole the blower will still run. It turns off the a/c compressor but just blows air. If I leave it off it will intermittently change speeds or stop but comes back immediately.
Could this be the result of a failing CCU, resistor, stuck relay, battery or the common ignition switch?
How many of you have experienced this issue? I am baffled by the problem and it seems likely it could be any of these.
I disconnected the battery in hopes the CCU will reset it self over night.
On a side note. about 20 minutes after noticing the blower these three CEL lamps illuminated for a brief second: PSM, ABS, and Brake all at the same time and never came back on. I ran durametric and it did not display any fault codes.
Related or unrelated.
Thanks for your help and input.
1999 996 Carrera 4
98,000miles
After some investigation I have narrowed down to the blower speed not responding to the CCU (Climate Control Unit).
Here are my symptoms: A/C compressor (on/off) and temp responds to the selected variables. All baffles function and direct air where selected. The issue issue I am having is I cannot control fan speed and if I turn off the climate control unit as a whole the blower will still run. It turns off the a/c compressor but just blows air. If I leave it off it will intermittently change speeds or stop but comes back immediately.
Could this be the result of a failing CCU, resistor, stuck relay, battery or the common ignition switch?
How many of you have experienced this issue? I am baffled by the problem and it seems likely it could be any of these.
I disconnected the battery in hopes the CCU will reset it self over night.
On a side note. about 20 minutes after noticing the blower these three CEL lamps illuminated for a brief second: PSM, ABS, and Brake all at the same time and never came back on. I ran durametric and it did not display any fault codes.
Related or unrelated.
Thanks for your help and input.
1999 996 Carrera 4
98,000miles
#2
Race Director
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This was the very first symptom that my ignition switch was going south.
With the car started, try turning the key VERY slightly - 1 or 2 degrees - CCW and see if the fan starts behaving again.
Your car will act as though possessed by demons as the switch deteriorates further.
With the car started, try turning the key VERY slightly - 1 or 2 degrees - CCW and see if the fan starts behaving again.
Your car will act as though possessed by demons as the switch deteriorates further.
#3
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I have read about the ignition switch keeping the HVAC blower off but nothing about keeping it running or not being able to change speeds. Would a faulty ignition switch do what i described?
I did not explain that the blower will stop with the ignition power off (function normal).
I did not explain that the blower will stop with the ignition power off (function normal).
#7
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#9
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Alpine, 5 bucks says the ignition switch. You in?
The Germans managed to miniaturize every electrical gremlin that has plagued British cars since the dawn of the internal combustion engine and entomb them in that damnable switch - I think it's a security feature intended to discourage reverse-engineering. Once they start to get out...
The Germans managed to miniaturize every electrical gremlin that has plagued British cars since the dawn of the internal combustion engine and entomb them in that damnable switch - I think it's a security feature intended to discourage reverse-engineering. Once they start to get out...
#10
Race Director
#11
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Alpine, 5 bucks says the ignition switch. You in?
The Germans managed to miniaturize every electrical gremlin that has plagued British cars since the dawn of the internal combustion engine and entomb them in that damnable switch - I think it's a security feature intended to discourage reverse-engineering. Once they start to get out...
The Germans managed to miniaturize every electrical gremlin that has plagued British cars since the dawn of the internal combustion engine and entomb them in that damnable switch - I think it's a security feature intended to discourage reverse-engineering. Once they start to get out...
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
#12
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![Roll Eyes (Sarcastic)](https://rennlist.com/forums/images/smilies/rolleyes.gif)
Now wouldn't be too bad if I found Lambo logo's on Porsche parts but then reliability would probably suffer.
#13
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Unfortunatley, this is going to be the norm moving forward. Same thing with Lamborghini's. Kinda cheapens the fact that you pay $150k++ and you find Audi logos everywhere. ![Roll Eyes (Sarcastic)](https://rennlist.com/forums/images/smilies/rolleyes.gif)
Now wouldn't be too bad if I found Lambo logo's on Porsche parts but then reliability would probably suffer.
![Roll Eyes (Sarcastic)](https://rennlist.com/forums/images/smilies/rolleyes.gif)
Now wouldn't be too bad if I found Lambo logo's on Porsche parts but then reliability would probably suffer.