Fan motor- power one side..can I save it?

[Overdraft]

All..I have power on one side of my fan motor...but not the other.  Do I assume the fan motor is cooked?  Any tricks to bring it to life?  That would be a nasty job to swap it out..:(

[Mike Self]

A little more explanation is needed from you...only one of the two terminals on your fan motor is hot; the other one is the ground.  So you should only have one hot lead. 

 

It may be that your ground wire is no longer grounding; you can check this quickly by running  jumper wire from the ground terminal (at the appropriate motor brush holder) to a known good ground.  If the motor now works, you just need to replace the ground wire and you're set.  

 

If it's something different, please elucidate further.

 

mike

[esty]

 

[John76]

Here is a sketch of the blower motor circuit. 

Check the power connection to the circuit board (Green/brown wire). The connector tends to break for some reason.

Also be sure to check the grounds....very important or you get a very slow motor or no motor at all.

 

['76mintgrün'02]

Once you get the wiring sorted out, you might want to lubricate the fan motor. 

 

 

[Overdraft]

Ran the temporary ground....so I side is hot......then from the other side to ground I run a conductor...and it doesn’t fire up.

['76mintgrün'02]

Does the fan spin free if you push on it?

 

If it feels tight, it might like a little squirt of something juicy... such as Tri-Flo. 

[ray_]

55 minutes ago, '76mintgrün'02 said:

Does the fan spin free if you push on it?

 

If it feels tight, it might like a little squirt of something juicy... such as Tri-Flo. 

[Overdraft]

So the grey/ brown terminal was broken on the resistor board - and even when I held the conductor on the tab, I could not make that fan start try as I might...either that way OR per my previous post, grounding the fan so I have to assume the fan is seized (because grounding it when I had power at it I couldn’t make it go either). I haven’t opened up the box...but it appears the job I was dreading is upon me.  Can you buy just the board and the motor and rebuild everything else in situ?  The foam gaskets and operation of the flaps are pretty good actually......but alternatively- after searching and reading on the subject - is there a complete heater box/ fan kit you can buy?  

Edited May 16, 2021 by Overdraft

[Gordon]

Here's a good discussion on this topic.

https://www.bmw2002faq.com/forums/topic/63222-heater-blower-fan-motor/

[John76]

9 hours ago, Overdraft said:

terminal was broken on the resistor board

I had to convert the broken female spade on the resistor board to a male by snipping off the rounded (curled) portion and replacing the male spade on  the wire with a female connector.

This may fix the electrical problem, but then you need to make sure the motor is spinning freely (and in the right direction).

John

[Overdraft]

1 hour ago, John76 said:

I had to convert the broken female spade on the resistor board to a male by snipping off the rounded (curled) portion and replacing the male spade on  the wire with a female connector.

This may fix the electrical problem, but then you need to make sure the motor is spinning freely (and in the right direction).

John

I will try that next...but I think the fan motor has seized...certainly it doesn’t spin freely.  I appreciate everyone’s ideas and experiences.

[ray_]

8 minutes ago, Overdraft said:

I will try that next...but I think the fan motor has seized...certainly it doesn’t spin freely.  I appreciate everyone’s ideas and experiences.

Even mine? ?

[Overdraft]

I have now soldered (Mgivored) the ground...but I have lost the 12v I had at the hot side of the fan motor ?  I have added WD 40 to the motor...and it certainly is easier to move...it doesn’t  spin freely however but per say but moves freely if that makes sense  - just don’t know how free they are supposed to move.  I will follow the circuit diagram John posted earlier and see if I can sort it out.  I can’t get 12v when I put my tester in the socket of the panel light either.  Is that a clue? ....or am I just avoiding the inevitable to replacing that blasted motor?

Edited May 24, 2021 by Overdraft
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[dlacey]

Probably a fuse now the motor is stiff and drawing amps...