How does Automatic Air Con Thermotronic adjust left/right fan speed?

Submariner1

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I wondered how you can have different fan speeds left and right, when the air blower motor has twin impellers on the same shaft!

I took out the blower motor to clean it out, and expected to see twin impellers and twin motors.
Nope one motor, a single shaft protrudes either side, and an impeller on each end.

So how can it have fan speed 1 on the left and fan speed 4 on the right? There doesnt seem to be any other fans in the system. Just intrigued!

Worth cleaning out, as I found a fair few bits of dried leaves, a bit of dust and carbon brush dust and reassuringly no water stains :).

Sometimes on start up I had a slight noise for a few seconds or until one speeded up the fan.
So I greased the surround of the shaft as it goes into each bearing.
Whether its the lithium bearing grease or the removal of the leave debris ... but now its silent :):)
So worth doing.
 

Craiglxviii

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Twin rotors? A clutch on each shaft? It’s German, don’t rule out highly complex design!
 

dreadlockdw

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I don't believe they can have different left and right fan speeds. If they had then surely the unit would have separate left and right switches to operate them independently when in manual mode.
 

peterws1957

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I don't believe they can have different left and right fan speeds. If they had then surely the unit would have separate left and right switches to operate them independently when in manual mode.
The CL does have separate left and right hand switches, and work independently with several fan speeds.
 

Botus

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sounds strange....

mine has two distinctly different speeds / air flow and sound.... I don't think its flaps
you can have almost silent one side and jet engine the other
 

alexanderfoti

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Definitely one blower:
145702122243423800.jpg
 

Craiglxviii

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af how do you get variable fan speeds on each side of the car with one motor?
Either two rotors orclutched half shafts. Looks like two rotors from that image.
 

alexanderfoti

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IMO its controlled entirely with flaps. There are only two wires to the motor so control must be done elsewhere.
 
OP
Submariner1

Submariner1

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IMO its controlled entirely with flaps. There are only two wires to the motor so control must be done elsewhere.
Imo Alex must be right.
No other explanation, I only asked in case there was another one of these complete blower units somewhere else.
WIS and EPC dont show any other.
 

alexanderfoti

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Imo Alex must be right.
No other explanation, I only asked in case there was another one of these complete blower units somewhere else.
WIS and EPC dont show any other.

Mine has another self contained unit In the center console for the rear set passengers. It had a blower, ac evaporator and heater matrix with its own set if duo valves
 

peterws1957

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Mine has another self contained unit In the center console for the rear set passengers. It had a blower, ac evaporator and heater matrix with its own set if duo valves
Now you're just bragging...:)
 

Botus

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Yep mine looks like this and both left and right turbines on the same shaft, well they turn together. No seperate wires for any kind of clutch.


if you change the air flow or angel of dangle coming in, it might work
 

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