Climate Control Fan Speed Not Working Correctly

[Z8911]

The fan speed control knob isn't working properly. Only the highest fan setting works. No other fan speeds work. Please tell me I don't need to replace the entire climate control unit to fix this issue...

[StuM]

Did you ever figure this issue out and get it corrected? I have the same issue, but only intermittently. Thanks,

[Z8911]

We’re pretty sure it’s the resistor for the fan. Very common issue on other models as well. The highest setting for the fan works because it’s a straight shot from the switch to the fan without going through the resistor. Mine was working intermittently as well. Haven’t installed the new resistor as mine is working at the moment and my mechanic has a bunch of my other projects that are more of a priority at the moment.

[boomster]

The symptoms you describe sound very much like a failing Final Stage Resistor, often referred to as a "hedge hog" due to its spikey appearance. These are known to fail quite regularly in contemporaneous E39 and E46 BMW's, so it is highly likely the cause. I replaced one in my son's 2001 330ci a number of years ago, it is a fiddly job up under the dashboard, I have no idea how inaccessible it might be on the Z8.

https://www.youtube.com/watch?v=7_D-Ki_Kk2k

[StuM]

The symptoms you describe sound very much like a failing Final Stage Resistor, often referred to as a "hedge hog" due to its spikey appearance. These are known to fail quite regularly in contemporaneous E39 and E46 BMW's, so it is highly likely the cause. I replaced one in my son's 2001 330ci a number of years ago, it is a fiddly job up under the dashboard, I have no idea how inaccessible it might be on the Z8.

https://www.youtube.com/watch?v=7_D-Ki_Kk2k

.......
....So, does anyone actually know where this resistor resides and the actual replacement procedure? Seems it vastly differs on the many BMW model lines.
Thanks,

[Z8911]

My mechanic was a master technician for bmw and has a physical copy of the Z8 workshop manual. I’ll ask him to bring it to the shop and see if there’s directions on how to get to it. I’ll report back when he brings it.

[StuM]

My mechanic was a master technician for bmw and has a physical copy of the Z8 workshop manual. I’ll ask him to bring it to the shop and see if there’s directions on how to get to it. I’ll report back when he brings it.

...
Well, I bought an OEM HVAC resistor module online and replaced the faulty unit yesterday. Not necessarily overly difficult, but it was a bit tricky. Had to go through the cabin filter(s) frame housing. Pulled the filters for full, yet tight access. Removed the retaining straps on the curved blower fan housing, moved it out of the way and could then reach down and in with needle nose pliers to pull out the old resistor. (Blue in color and you really need a tilting mirror to get a good look at it. It sits on the lower side of the fan housing, in the very center between the two circular fans. Then plugged in the new one. (Four blade type connectors.) Again, difficult to see and position, so it took a bit of blind positioning and working by feel to get it pushed in and secured. Numerous outbursts of *^%#@_= to help the process at times. Tested the fan speed switch and all was back to normal, so re-secured all the parts and tested underway. No leftover parts and no lost sockets or tools down in the depths of the engine compartment! Good as new! 👍

[boomster]

Well done! What prompted you to come at it from the cabin filter area rather than from under the dash? Hard to imagine there are any YouTube videos on this procedure for the Z8.

[2112]

Fantastic!

any chance you grabbed a picture or two?

[StuM]

Well done! What prompted you to come at it from the cabin filter area rather than from under the dash? Hard to imagine there are any YouTube videos on this procedure for the Z8.

.....
From the looks of it, I don’t think you can access the resistor area from inside the car. It’s sitting right in the fan box, within the engine compartment. I know some other models of BMW do have it mounted on the inside, but not our Z8’s.

- - - Updated - - -

Fantastic!

any chance you grabbed a picture or two?

. Will try to grab a few pic’s next time I open things up to check on things.

[2112]

.....

. Will try to grab a few pic’s next time I open things up to check on things.

thanks