[MIM5]

2007 335i E92

Today while driving, I noticed that my heater fan was acting up. As I speed up or slow down the heater fan would slow down and not blow as hard, then all of a sudden start up blowing normally again. This would also happen on some slight bumps in the road also. I also noticed that when I turn the fan setting to the 4th block that is the highest the fan will go. If i turn it up higher, the fan does not blow any harder.

Has anyone ran into this problem or have an idea of what is wrong? I have the JB4 USB running through the fire wall, and was wondering would that cord ever get into the way of the heater fan?

After driving around awhile I noticed that this would happen when I slow down to a stop when the rpm would reach close to idle. The fan would slow down or stutter then speed right back up to normal. Even when I sit in park and rev it up, when the rpm's drop to idle the fan slows down then goes back to normal. Doesn't happen if I'm anywhere above idle. Now I'm really stumped on what this could be?

[MIM5]

Bump for some help please

[RoundelM3]

It's the regulator that's part of the fan unit - it sits up under the dash behind the glovebox area. You can get a new one for about $160 from getbmwparts.com and it includes the regulator plus the fan assembly itself.

[farb]

is your car overheating as well? if so, then your water pump needs replacing.

[WickedB]

Originally Posted by roundel335

It's the regulator that's part of the fan unit - it sits up under the dash behind the glovebox area. You can get a new one for about $160 from getbmwparts.com and it includes the regulator plus the fan assembly itself.

+1 I have the exact same issue and this is what I've read the issue is.. makes sense.

[BMWM.D.]

Originally Posted by roundel335

It's the regulator that's part of the fan unit - it sits up under the dash behind the glovebox area. You can get a new one for about $160 from getbmwparts.com and it includes the regulator plus the fan assembly itself.

Definitely could be the blower resistor. But before it's condemned, make sure there aren't any voltage issues when this is happening. Especially since you say it happens when at idle speed, it could be the consumer cut-off function reducing the blower speed in response to system voltage. When this happens, the blower will only go up to about half speed. I haven't seen these cars having too many resistor issues. Was a huge problem with the E46 and other models that shared it's climate control system.

[e2d]

Originally Posted by Justohigh

2007 335i E92

Today while driving, I noticed that my heater fan was acting up. As I speed up or slow down the heater fan would slow down and not blow as hard, then all of a sudden start up blowing normally again. This would also happen on some slight bumps in the road also. I also noticed that when I turn the fan setting to the 4th block that is the highest the fan will go. If i turn it up higher, the fan does not blow any harder.

Has anyone ran into this problem or have an idea of what is wrong? I have the JB4 USB running through the fire wall, and was wondering would that cord ever get into the way of the heater fan?

After driving around awhile I noticed that this would happen when I slow down to a stop when the rpm would reach close to idle. The fan would slow down or stutter then speed right back up to normal. Even when I sit in park and rev it up, when the rpm's drop to idle the fan slows down then goes back to normal. Doesn't happen if I'm anywhere above idle. Now I'm really stumped on what this could be?

Check this page out.. Pretty helpful and talks about the example you describe.

http://blog.bavauto.com/12282/bmw-an...w-to-diagnose/