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New Year drama! E53 HVAC blower replaced...but problem <roll eyes>

Posted: Fri Jan 22, 2021 3:20 pm
by x5dom
Hi. Hope all keeping safe, well and sane.

My E53s main blower had been playing up for about a year or so. It is pretty much constantly running with auto a/c on and with15yrs/115k miles under it's belt it's done well really.

Symptoms - would just suddenly stop working despite control panel still illuminating/changing values etc. Wishing it was just the FSR, in my case it turned out not to be. Case of an ageing blower motor/worn brushes. I replaced the original BMW FSR though just in case.

I managed to get the blower going again by removing the cabin air filter tray from the bulkhead gaining restricted access to the blower blades. Enough for me to spin them by hand, spraying a bit of contact cleaner in there and eventually coax the blower into life again. Had worked a treat a couple of times over 2020 as wanted to avoid a dash out scenario. December it stopped again and that was it. No luck with the spinning this time. Resided to the fact it was dash out new blower motor time in Jan.

I've successfully removed the whole dash (also involves airbag removal so disconnected battery earth from spare wheel well). Have fitted a brand new Febi Bilstein blower and a brand new Meyle FSR. Now here's my problem. When I connect the battery earth the new blower immediately kicks in on full power. Great to hear a blower again but not constantly. :roll:

The a/c control panel fan speed rocker switch will not reduce it's speed or indeed switch it off. No difference if I have the ignition on or not. It is just constantly live. I have tried another brand new FSR just incase had a faulty one but no. Obviously if I unclip the FSR power is cut to the motor and therefore does stop.

I'd like to get her all back together again asap so any ideas where I'm going wrong? Why does the motor now have a permanent live. My only other thoughts are to try another a/c control panel &/or the ignition switch module?? But don't really want to be just chasing my tail and forking out unnecessarily.

Any help/pointers appreciated :thumbsup:

Dom

Re: New Year drama! E53 HVAC blower replaced...but problem <roll eyes>

Posted: Fri Jan 22, 2021 9:59 pm
by henrym3
My money would be on the control panel. They do go wrong, ideally if you could swap with a working one before buying a second hand one. Diagnostics won’t necessarily tell you what the fault is.

Re: New Year drama! E53 HVAC blower replaced...but problem <roll eyes>

Posted: Sat Jan 23, 2021 6:42 am
by Themoog2
I'm not Sherlock Holmes but the evidence clearly shows that the control panel is at fault... Just buy a used one.

Re: New Year drama! E53 HVAC blower replaced...but problem <roll eyes>

Posted: Sat Jan 23, 2021 9:32 am
by Greydog
Seems like your rebuilding the complete system what a pain for you but on the plus side we get a load of knowledge on the forum.

As it is all apart (I assume it is) did you try the old motor to see if that reacts the same way (if you can coax it into life that is) that way it would either confirm the panel at fault or not? If the old motor is controllable it would point towards the new motor.