Diagnostics possible for heater blower not working?

andynics1

andynics1

A2OC Donor
Does anyone know if vag-com will diagnose the problem I have.

The heater blower stopped working via the climate control unit. The blower on the display goes up but the blower doesn't come on. The bars then fall away to nothing .

A 12v feed direct to the fan works properly, also the resistor unit has been parted out and that doesn't fix it, iv also replaced the climate control unit itself and that isn't at fault.

Also putting a volt meter on to the fan unit, it receives 8.5v from the resistor unit when I turn the fan on but then drops to zero when the fans bars disappear!!! It's driving me nuts as I don't know what else to replace to fix this...

Can anyone helps?


Kind regards


Andy
 
Replace Cabin Heater Fan Unit

I really think you need to Replace Cabin Heater Fan Unit (Item 9 - Not item 6 which is highlighted) that is sited behind the glovebox.
 

Attachments

  • Heater Blower0001.pdf
    560.2 KB · Views: 1,069
Yes (It was on ours)

The motor gets sticky (I am sure there is a more technical term) and the 8.5v from the resistor cannot over-come the physical resistance but the 12v direct feed can.

Have you tired to move the fan by hand - it should move freely.
 
I read most of the posts on this subject after my Cabin Blower failed exactly as described by many here ( bars on climate controller went up as + button pressed but fell away to zero after about 5 seconds) fan non-operational
I stripped out glove box and opened re-circ damper to find that fan was not seized but a little stiff. With multi-meter across power supply ( now disconnected from blower )the climate control held the fan "bars" and the voltage went up above 12V when all bars were displayed. When I connected a spare 12V battery to the fan it worked at full power, but reconnecting the supply from the car the fault was still evident.

I stripped out the fan and the connected finned control box. I lubricated the fan motor at both bearings with light oil and let it sit, then operated on a full 12V for a few minutes. When I assembled all the parts in the footwell to test -SURPRISE-! the rig all worked exactly as it should!

After full re-assembly the fan is now working correctly. My guess is that the bearings were dry and tight giving too much friction. The climate unit must sense the motor current as too high (motor seized) and take the power off to prevent overheating (my supposition ? )

Anyone wishing to avoid the back-breaking removal of the fan could try carefully drilling a hole big enough for the straw on WD40 can in the plastic fan casing about 5mm above the centre pimple. The back bearing on the fan motor is directly behind and you will be able to deliver some lubricant to at least one of the bearings to see if this will cure the problem first.

Incidentally a good repair can be made to the worn surface on the "graphically challenged" fan speed rocker switch by carefully prying off the surface rocker with a 30 thou feeler blade, stick black vinyl insulating tape in two patches having first cleaned the surface with meths. Then at top and base cut out with a fine scalpel the plus and minus graphic. It looks just fine in both daylight and darkness. No need to remove the unit and costs about 1p/takes 5 minutes.
Happy New Year
 
You must log in or register to reply here.
Back
Top