Heater blower motor

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Lukeh17
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Heater blower motor

Post by Lukeh17 » Mon Nov 27, 2017 6:49 pm

Hi,

When I turn the heater fan switch knob, the heater doesn't come on 1st and 2nd speed, but tries to come on on 3rd but fails to do so. I kept trying and eventually the fuse blew but the fuse looked ok on inspection, before being destroyed!!

Is this the heater motor?

https://www.vwheritage.com/251819015-he ... co-mk1-mk2

Also, would it be worth getting the heater fan switch? - I don't think this is the problem, as it seems to be a heater motor issue, but just to be sure

https://www.vwheritage.com/171959511-sw ... ta-mk1-cab

Thank you



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unknownmale
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Re: Heater blower motor

Post by unknownmale » Mon Nov 27, 2017 8:21 pm

Not sure about the VW ones but most heater controls work by placing a resistor inline with the fan circuit, the highest setting is typically just straight through (no resistance), Newer systems use duty cycled signals to vary fan speed.

I would suggest removing the fan first to ensure it's not just clogged up, it's also worth testing the power at the fan at the 3 speed settings as the controller could be the issue.

Having the fan clogged up would cause it to draw excessive amperage and pop the fuse, so it sounds like something stopping the fan could be likely. It's also possible that a few of the commutator bars on the motor are gone (You can test this simply by helping the fan along will power is connected).

Always best to do the easy checks before buying a bunch of parts!


- David

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Re: Heater blower motor

Post by mr.brown » Mon Nov 27, 2017 11:30 pm

If you take a look at the blower fan from the engine bay you will see the resistor as mentioned above. This is what it looks like

Image

although it will be mounted to the fan. It definitely sounds like the resistor is the issue but an easy way to check the fan is to run a 12v wire direct from the battery to the positive on the fan motor (where the yellow wire spade terminal connects to).



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scrumpyone
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Re: Heater blower motor

Post by scrumpyone » Tue Nov 28, 2017 10:17 am

If you end up having to replace the motor, first check out Eefy's thread on how to do it.
You will save yourself a lot of cussing.


Dave

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Lukeh17
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Re: Heater blower motor

Post by Lukeh17 » Tue Nov 28, 2017 11:23 am

Thanks for the tips guys. I will make a check and see if the fan is clogged and check the resistor. Thanks again :-)



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Re: Heater blower motor

Post by mark1gls » Tue Nov 28, 2017 11:29 am

Yes remove the plastic scuttle cover and you will see the fan motor, you may have a white plastic cage over the top, remove this and see if you can turn the fan by hand, it should spin freely.


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Lukeh17
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Re: Heater blower motor

Post by Lukeh17 » Tue Nov 28, 2017 11:16 pm

I take it the fan is near the bulkhead then. What's the difference between the blower fan in the engine bay and the fan connected to the motor or is it the same, but just accessed from different ways?

If I need a resistor, where can I get it from?

I will start by trying to see if it's a clogged fan, then I will move onto the resistor and finally the motor.



mark1gls
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Re: Heater blower motor

Post by mark1gls » Wed Nov 29, 2017 10:55 am

Yes it's near the bulkhead, just below the vent holes cut into the bonnet as that is where the fresh air gets in. The fan is attached to the motor and access is via the scuttle panel in the engine bay (underneath the plastic rain cover)

You can see where it is in the 1st picture and lots of pictures of the fan and motor as it's a complete unit.

https://www.google.co.uk/search?q=mk2+s ... jAD#imgrc=_


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Lukeh17
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Re: Heater blower motor

Post by Lukeh17 » Wed Nov 29, 2017 12:46 pm

mark1gls wrote:Yes it's near the bulkhead, just below the vent holes cut into the bonnet as that is where the fresh air gets in. The fan is attached to the motor and access is via the scuttle panel in the engine bay (underneath the plastic rain cover)

You can see where it is in the 1st picture and lots of pictures of the fan and motor as it's a complete unit.

https://www.google.co.uk/search?q=mk2+s ... jAD#imgrc=_
Thanks Mark - do the wires on the right belong to the resistor?



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Re: Heater blower motor

Post by scirocco333 » Wed Nov 29, 2017 4:08 pm

I had the same problem and worked on it a few months ago. (1981 model).
I took the plastic shroud off (label the vacuum tubes!) and discovered the blower was full of debris. I shop vac’d it out and the two piece housing over the cylindrical fan was fiddly to put it back together. Take pictures. Before I put the shroud back, I tested the motor and discovered my switch didn’t work on high. Replaced that and I was in business again. Do this on a warm day if possible because it’s easy to crack the shroud like I did.


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Lukeh17
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Re: Heater blower motor

Post by Lukeh17 » Wed Nov 29, 2017 8:20 pm

scirocco333 wrote:I had the same problem and worked on it a few months ago. (1981 model).
I took the plastic shroud off (label the vacuum tubes!) and discovered the blower was full of debris. I shop vac’d it out and the two piece housing over the cylindrical fan was fiddly to put it back together. Take pictures. Before I put the shroud back, I tested the motor and discovered my switch didn’t work on high. Replaced that and I was in business again. Do this on a warm day if possible because it’s easy to crack the shroud like I did.


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Thanks for the advice buddy :-)



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Re: Heater blower motor

Post by mark1gls » Wed Nov 29, 2017 10:02 pm

Yes the Polo mint size tube with the yellow wires coming from, the problem can be getting to the wires as they go from the fan motor into the cars interior and onto the fan switch.

My car has no fan at speed 1 and I have a spare resistor to fit but I not be able to get the wires out, I’m taking my dash out this winter so that is when I plan on changing my resistor.
There maybe a easier way to do it on a Mk2 as my car is a Mk1?


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Lukeh17
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Re: Heater blower motor

Post by Lukeh17 » Thu Nov 30, 2017 2:17 pm

mark1gls wrote:Yes the Polo mint size tube with the yellow wires coming from, the problem can be getting to the wires as they go from the fan motor into the cars interior and onto the fan switch.

My car has no fan at speed 1 and I have a spare resistor to fit but I not be able to get the wires out, I’m taking my dash out this winter so that is when I plan on changing my resistor.
There maybe a easier way to do it on a Mk2 as my car is a Mk1?
Thanks Mark, I will try from engine bay and then may have to take the dash out, to do the resistor, fingers will be crossed that I can do it from the engine bay ;-) :-D



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Re: Heater blower motor

Post by mark1gls » Thu Nov 30, 2017 3:48 pm

Clean out the fan and check it spins freely before doing anything major, could be a cheap and simple fix if the fan is just full of leaves and a good spray of WD40 on the motor end frees it up.


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Lukeh17
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Re: Heater blower motor

Post by Lukeh17 » Fri Dec 01, 2017 10:42 am

mark1gls wrote:Clean out the fan and check it spins freely before doing anything major, could be a cheap and simple fix if the fan is just full of leaves and a good spray of WD40 on the motor end frees it up.
Thanks Mark :)