Blower motor wont come on unless I hit a bump

[arctic28]

I've done a bit a searching but no one seemed to have a similar problem. My blower motor only comes on when I hit bumps and will not turn on otherwise. When it does come on the fan speeds work so that makes me think it's not the FSU or the control unit. So is my blower motor dead or is it something else?

Thanks.

[dorkymood1]

Sounds like it possible that the blower motor is bad, possible whats happening is your
motor stops on a dead spot on the armature and when you hit a bump it causes it to
move to a good spot and therefor starts. Long as it's running it should continue to run but when you turn it off it's hits those dead spots again. Not likely a loose wire or it would work off and on until vibrates loose or tightens. It would not hurt to pull the motor cover off and run 12v directly to the fan several times to verify that the motor is bad if it won't start and you spin it a little and it does, then motor is bad. Not too difficult to replace, can be pricey if you go back with oem motor, I bought one on ebay for less than a $100. If you do it yourself make sure you get bently manual and read carefully before you start and follow directions, I didn't and I lost some clips and messed you the cover. Good Luck !

[arctic28]

Thanks for the info. I might try to pull it apart this weekend and test it like you said. I just checked pelicanparts.com and they have a motor for $130.

[flyfishvt]

You have digital climate control so...

Test your fuses.

Does the head unit seem to work ok all the time? Does it respond when you change settings? Or does the head unit kick in and out when you hit bumps? If it works ok and isn't affected by bumps then you need to look at the FSU and the fan.

If the headunit kicks in and out when you hit bumps then you'll have to start there. It could be as simple as a bad solder joint (well known issue with digital) or a loose connection in the back.

If you can rule out the head unit then first check the connection at the FSU. its a lot easier to get at than than the blower fan. You could just have a dirty/loose connection at the FSU or the FSU could be faulty. Typically when the FSU goes bad you will be no fan or it will run very irratically.

if everything checks out at the FSU then move on to the fan itself.

[ECSTuning]

We have both Blower Motors and blower motor resistors (FSU) replacements available below... Our blower motors are available as low as $112...

Click HERE for more information.


Please let us know if you have any questions! Feel free to shoot me a PM or email.

Best,
Joe

[arctic28]

My control unit works just fine, I did have to replace the capacitor in it a few months back though (this). Another thing I forgot to mention is that the blower motor has been making weird noises when running since the beginning of February, which is another reason why I think the motor is just going out. I did jiggle the connection on the FSU and nothing seemed to happen. I don't really think it's the FSU because from everything that I've read is that when the motor is on the only speed that works is full blast and when mine does come on the speeds work fine. I'm thinking that I'll double check the fuses and hook up a 12v source this weekend and see what comes of it. I appreciate the responses.

You have digital climate control so...

Test your fuses.

Does the head unit seem to work ok all the time? Does it respond when you change settings? Or does the head unit kick in and out when you hit bumps? If it works ok and isn't affected by bumps then you need to look at the FSU and the fan.

If the headunit kicks in and out when you hit bumps then you'll have to start there. It could be as simple as a bad solder joint (well known issue with digital) or a loose connection in the back.

If you can rule out the head unit then first check the connection at the FSU. its a lot easier to get at than than the blower fan. You could just have a dirty/loose connection at the FSU or the FSU could be faulty. Typically when the FSU goes bad you will be no fan or it will run very irratically.

if everything checks out at the FSU then move on to the fan itself.

[5OnTheFloor]

Wow, my blower motor just started doing the exact same thing a few weeks ago. It's making a rumbling noise too, so I'm guessing I need a new blower motor.

[flyfishvt]

I don't really think it's the FSU because from everything that I've read is that when the motor is on the only speed that works is full blast

You didn't read my post then. If you have analog controls it uses a Blower Motor Resistor and when that fails the only speed you get is full blast.

You have digital controls that use an Final Stage Unit. When the FSU fails you will have either no fan at all or the fan speed will be all over the place no matter what you set it at.

But it seems that you left out an important bit of info and I would say since its making noise that you need a new fan.

[arctic28]

You didn't read my post then. If you have analog controls it uses a Blower Motor Resistor and when that fails the only speed you get is full blast.

You have digital controls that use an Final Stage Unit. When the FSU fails you will have either no fan at all or the fan speed will be all over the place no matter what you set it at.

But it seems that you left out an important bit of info and I would say since its making noise that you need a new fan.

I have digital controls and when the fan is on the controls work like they are supposed to.

[darth510]

right!i had this problem myself! Digital controls and the heater blower only worked when it felt like it and came on if i hit a bump etc, had a look around on here and pelican and seems to be a common problem with the FSU, the pics showed above the pedals on a US/RHD car, so mine being a UK/LHD i located mine in the passenger footwell! went to a breakers yard and got a replacement one-guy did'nt even charge me!! 20 minute job and blowers blows like a good un-Job done! only hex in with two screws and one plug

[darkislight]

I had the same problem in my old e30. The brushes on the motors comutator were worn and would stop on dead spots and then the motor would only start when the car hit a bump and the vibration from said bump would start the blower motor.

I finally changed the blower motor for a used $25 unit. Lucky me.

You could probably change the brushes if you can get the replacements or have the patience. I purhased a spare motor as backup just in case.

It's a 1-2 hour job to replace the motor.

[Leitrimlad]

What did you change to fix your problem?!!

[3lm3rom3ro]

finish the d*** thread guys this why we make them in the first place to learn!

[Eric93se]

This can either be the FSU resistor pack or the blower motor. On the blower motor either the brushes are worn and make intermittent contact or people have had wires disconnect. On the FSU, it is actually serviceable, solder contacts fail and they can be re-soldered, on mine I removed all the old solder and freshly soldered them all. There is a thread on fixing the FSU, you basically carefully scrape the rubber compound from the circuit board and expose the solder junctions, do it carefully.

[pizzaman09]

Not on a BMW but I had a blower motor go on a car of mine in very similar fashion. It would only work well if pulling G's turning a corner to the left. It would kind of work going straight and die all together when turning right. The commutator in the motor had gone bad. A new motor fixed it right up.

[shoman24v]

Brushes on the motor are worn out. You need a new motor.

[babenja318is]

You aren't the only one. Mine does the same thing. I've already started shopping around for a new motor, but having more ideas to test before dropping the money.