Hi all,

 

I've had the issue twice before, both times it was a resistor fail because of the 4th speed only working.

 

This time it's different 3 and 4 speeds work so does this mean it's a switch fail and not a resistor?

 

Thanks in advance

No, it's still the resistor pack.

If the resistor pack keeps burning out, it could be that the motor bearings are a bit tight & need some lubrication.

 

 

The motor is fine, as 3 and 4 work flawlessly

Has the pollen/cabin filter been changed lately? Blockage can help the resistor overheat.

Resistor can fail in several places; one way just affects speed 1, another takes out 1 and 2, and finally 1, 2 and 3. 

Speed 4 works even in the absence of the resistor as it has a direct link from the switch.

 

 

Ignore the big arrows, they were for something else. N24 is the resistor pack, V2 the fan motor.

Diagram is for an 06 Mk1 so ignore the fuse number too, that'll probably be different.

Edited 12 August, 20205 yr by Wino

I changed pollen filter about 2 weeks ago, I bought it on eBay and it's lasted 4 years which was 3½ years more than a genuine one.

2 minutes ago, fabia_simon said:

I bought it on eBay and it's lasted 4 years which was 3½ years more than a genuine one.

The pollen filter or the resistor?

1 minute ago, Wino said:

The pollen filter or the resistor?

Sorry the resistor I got from eBay

Pollen filter from euro car parts

 

The remaining possible causes of resistor failure  if pollen filter isn't blocked seem to be fan taking too much current due to physical restriction such as PipH suggests above, short-circuit in motor windings, or because supply voltage is above spec.  The latter seems unlikely, but check voltage across battery terminals with engine running just to rule out alternator misbehaviour.

 

 

Edited 12 August, 20205 yr by Wino
sp

46 minutes ago, Wino said:

The remaining possible causes of resistor failure  if pollen filter isn't blocked seem to be fan taking too much current due to physical restriction such as PipH suggests above, short-circuit in motor windings, or because supply voltage is above spec.  The latter seems unlikely, but check voltage across battery terminals with engine running just to rule out alternator misbehaviour.

 

 

Without getting to technical the cheapest option is a new resistor. That's been the cause on every occasion since I've owned the car for the last 5 years

30 minutes ago, fabia_simon said:

That's been the cause on every occasion

Arguably it's a symptom rather than the cause, but yeah, you'll have to change it anyway, even if you don't want to delve deeper and try to stop it happening again.

 

Our Fabia still has its factory original resistor pack, 15 years on, so they can last well when everything else is behaving itself.  Or perhaps they just made them better way back then.

 

 

Edited 12 August, 20205 yr by Wino