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Discussion Starter #1
Just thought I'd share my experiences with this one, as I haven't seen it on the forum (sorry if I've missed it).

"Normal" T5 Fan Blower Check
To find out if your getting different (and the right) voltages from your fan speed controller, you normally put a voltmeter across the 2x terminals of the fan blower. The voltage I would expect to change dependent on the fan and corresponding resistor value.

Climatronic T5 Fan Blower Check
Not the case with the climatronic..

The voltage at the blower terminals remains the same, no matter what the fan setting on the display. Certainly the case with my multimeter. Could leave you thinking the fault lies elsewhere. It did with me.

But this is how it works:
1) The climatronic controller outputs PWM for fan speed. Pulse Width Modulation. Voltage is c. 12v but the duty cycle of the wave output changes. Commonly used for motor speed control these days.
2) PWM signal goes to the blue "Bitron" module next to the fan. This is essentially a power transistor output stage, cooled by the fan (if working!). Limited Can-bus diagnostics for fan.
3) The motor receives the Bitron PWM with enough "oommph" to power the motor.

In the end I hooked up an LCD oscilloscope and you can see some nice PWM waveforms, that change with the fan speed set by the controller.

So, it was the fan blower after all, and c. £230 later all was well with the world.

Useless info: The blue Bitron controller part number is the same used on the SUVs of VAG - Touareg, Q7, and Cayenne.
 

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hi, would anyone have the part number for the blower motor assembly for a VW T5 with climate control? I think mine has packed in!!

thanks
 
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