Polo Mk10 2019 Fan Resistor Pack

[brianmoooore]

You need to get an accurate value for the motor's current consumption, by connecting a DC ammeter in series with the feed to the motor or the resistor pack.
If the fan has it's own fuse, can also be done there, by pulling the fuse and connecting the meter across it's socket.

 

[johntheo]

Found 30A fuse but this only supplies the Blower control unit (J126) and only draws 1.58A at all blower speeds.

 

[johntheo]

Took another set of readings today but included the Alternator output, speed1 & speed2 with engine running don't make a lot of sense. One interesting point I noticed on speeds 3&4 is that the fan consumes ~ 2A less when blowing air through the heater matrix, presumably due of its resistance reducing the air flow.

20/03/2022​	Engine OFF​		20/03/2022​	Engine ON​
​	Battery​		​	Battery​	Alternator​	Battery​
Engine Off​	Amps​		Engine On​	Amps​	Amps​	Volts​
speed 0​	-4​		speed 0​	4​	5.5​	13.50​
speed 1​	-8.6​		speed 1​	5.3​	7.4​	13.46​
speed2​	-10.9​		speed2​	4.9​	9.2​	13.45​
speed 3​	-15.5​		speed 3​	4.5​	17.5​	13.44​
speed 4​	-21.7​		speed 4​	4​	26.5​	13.40​
	Fan Amps (calc)​			Fan Amps (calc)​
speed 0​	0​		speed 0​	-2.5​
speed 1​	4.6​		speed 1​	-1.9​
speed2​	6.9​		speed2​	0.3​
speed 3​	11.5​		speed 3​	9​
speed 4​	17.7​		speed 4​	18.5​

 

[johntheo]

You need to get an accurate value for the motor's current consumption, by connecting a DC ammeter in series with the feed to the motor or the resistor pack.
If the fan has it's own fuse, can also be done there, by pulling the fuse and connecting the meter across it's socket.

Took fan power readings from family 17 year old Polo (with original resistor pack), readings almost identical to present Polo, so would think "fault" elsewhere as I am now hearing of others with same problems.

9N Polo (2005), readings via M.meter. 3.7/6.3/10.2/16.2 (amps)
Mk 10 Polo (2019) , readings via VCDS. 3.9/6.2/10.8/17.0 (amps)

 

[johntheo]

I do not know how VW do this but on other makes I have seen the resistors are in a daisy chain so that:-
The slowest of 4 speeds uses R1 + R2 + R3,
The next slowest uses R2 + R3,
Next uses R3,
Fastest uses no resistors.
With this setup a failure in R3 causes all but fastest speed to fail.

Just for interest, I removed my resistor pack today and this is how the resistors are utilized, exactly as you have shown on utube. (terminals 1 to 4 from left to right)
speed 1, term. 2 to 1, R2+R3
speed 2, term. 3 to 1, R2 only
speed 3, term. 4 to 1, R1 only
Can't fathom why all three speeds fail together, R2 must fail to make both speed1 and speed2 fail together but speed3, is fed from term 4 to term 1 via the fusible link and R1 so one of these must also fail at the same time as speed 4 is the only one available once the pack fails.
Also term 1 (common) which goes to the fan via the fan switch becomes live (12V) once speed 4 is selected, don't know what this is for as the fan is fed directly from the fan switch (speed 4) and the fan runs on speed 4 with pack terminal block removed.

Also, would be grateful if someone can point me to a (mail order) motor factors as I just can't source a spare anywhere except the main dealers at £100, even mister-Auto sent me the wrong one as the (proper) code 2QO.959.263 seems to look for the wrong type.

 

[johntheo]

Edit: Got mixed up, its the thermal fuse that must be blowing.
speed 1, term. 2 to 4, R1+R2+R3
speed 2, term. 3 to 4, R1+R2
speed 3, term. 1 to 4, R1 only
Also term 4 (common) which goes to the fan via the fan switch becomes live (12V) once speed 4 is selected, don't know what this is for as the fan is fed directly from the fan switch (speed 4) and the fan runs on speed 4 with pack terminal block removed.

 

[johntheo]

 

[johntheo]

Finally figured out something at least, term 4 (+red wire) becomes live on speed 4 because its back fed from the directly switched supply from the fan switch, N24 is the resistor pack,now if only I knew what's causing the failures.