HVAC blower motor rpm issue and questions >>

[Cobra Jet]

I tried searching using the terms "HVAC and/or blower motor" and was not getting any decent hits (other than those needing to correct cables on the HVAC control head, etc).

Here's what I am experiencing w/ my HVAC blower motor.  When I turn on the blower motor to either # 3 or # 4 speed, the blower motor (or dash) has a horrendous vibration that occurs.  When I use fan control speed # 1 or # 2, it seems to operate normally w/ minimal vibration.

Has anyone experienced this issue and if so, what was the fix?

Is it possible one of the blower motor wheels (hamster wheel) is out of balance or something, which is causing the dash vibration when it's set to # 3 or # 4 speed?  Does the cavity in which the blower motor resides accumlate debris and maybe this is what could be throwing it off balance under higher motor revolutions?

How is the blower motor secured in the cavity - does it have anti-vibe mounts?

The entire HVAC system works great (proper air distribution, all cables & sliders work perfectly, A/C and heat functions fine too.  Only the blower motor vibrates my dash when on setting # 3 or # 4....


Any help is appreciated.

[BMWManiac]

I'm bumping this thread:

Today I was driving when I heard what sounded like my engine fan hitting my engine....so I stopped, pulled over and sure enough, everything was fine.

It turns out that my blower fan makes this horrible vibrating sound, like it is rubbing against something.  This obviously needs to be fixed, so how do I access the fan?  Do I have to remove the dash?!?

[twright]

You access the fan through the engine compartment.  It is located behind the wiring harness on the firewall.  It is not fun, but it will come out of there without removing the engine if you stand on one foot, close your left eye and begin chanting.

After you've done it the first time, its really not that hard.  The first time will produce bad swear words.

If you drive it to Indianapolis, I'll help you with it.