Cooler fan motors, switching stages, pre-resistors

Hi,

The radiator fans in the AXR engine with Climatronic control have two speed settings. It is said that a resistor is connected in series with the fan in the slower speed setting. Where is this resistor located?

Regards,
Sure, here is the translation of the text from German to English:

"Micha"

Integrated into the engine.

red/black = level 2
red/white = level 1

Hi,

Thanks for the information. Is it possible to access the resistance somehow? Is it possible to exchange this somehow?

Regards,
Sure, here is the translation of the text from German to English:

"Micha"

Hi!

While I don't know why you want to adjust the fan activation point, I would recommend a thermal switch from Hartmann Motorsport (if you intend to activate the fans earlier).

Otherwise, just cheerfully disassemble the attached control unit...

Hmm,

I've never seen a fan motor on a dissection table before. So, it depends on your own attempt .
You could also try measuring red/black against red/white; in that case, you'll get the resistance value directly according to the circuit diagram.
Unfortunately, I don't have a reference value.

There probably isn't any (electrical) resistance present.

In DC motors, it is common to use a separate coil package (or multiple packages) instead of a pre-installed resistor.

It's safer, more affordable, and more sensible...

Best regards, Georg.

At the very least, it is clearly marked as a resistor in the circuit diagram.

At the very least, it is clearly marked as a resistor in the circuit diagram.
Then it's clear.

It seems I was wrong with my assumption, and it wasn't necessarily related to vehicles.

Good to know, thank you.

Hi,

It's good to know how things should be, and what VW has made of it.

Thank you for the information.

Regards,
Sure, here is the translation of the text from German to English:

"Micha"

I wouldn't necessarily rely on the circuit diagram for that. I've seen far too often that circuit diagrams contain errors.

The internal structure of the components is usually only hinted at in the SLPs, and even in the other components where a specific internal structure is depicted, I would not rely on the accuracy of those depictions. Ultimately, the intention of SLPs is simply to represent the wiring in a reasonably accurate way.

If I roughly estimate that the two-speed fan draws about 25A at 12V on the higher setting, then it would likely draw around 12.5A at 6V on the lower setting (1/4 of the power). This means that the resistor would also have 6V and 12.5A across it, which would be 75 watts. The resistor would have to be quite large, which would significantly increase the motor's volume and cause it to heat up considerably. Therefore: I'm already assuming two winding outputs for the motor and no resistance!

Regards,
Guste.

Regarding the windshield wiper motor, I'm familiar with the principle of using differently arranged brushes to reduce the speed, likely due to the high starting torque required. Since VW definitely uses resistors in the blower motors for the heating/ventilation system (with a relatively small starting torque), I don't see any reason why a similar approach couldn't be used for the radiator fan. I believe that 75 watts can be managed by utilizing the existing airflow and using a wire resistance with a value of 0.48 ohms.

Who has ever disassembled a radiator fan motor and knows it for sure ?

'If I roughly estimate that the two-speed fan draws about 25A at 12V on the higher setting, then it likely draws around 12.5A at 6V on the lower setting (1/4 of the power). This means that the resistor would also experience 6V and 12.5A, which would equate to 75 watts. The resistor would have to be quite large, which would significantly increase the motor's volume and cause it to heat up considerably.' Therefore: I'm already assuming two winding outputs for the motor and no resistance!

That was also my first rough estimate.

The amount of effort required is not really small.

There are two different motor windings.

I took one apart about a year ago. There is no resistance involved.

It's not the same for all vehicles.
I have a large pre-resistance in the engine compartment.

In the SLP document, the text explicitly states "not all fan motors are two-stage with a pre-resistance"... But never mind. Mephisto might find him.

*Brushing off dust*

Here, I found a repair manual for the pre-resistor. While you don't necessarily have to proceed like the author does, you can quite clearly see the orientation in which the resistor is installed.

[url][/url]http://www.ms-kreativ.de/env/download/ReparaturGolfLuefterVorwiderstand.pdf{MARKER}