Blower motor fuse?

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Hefeweizen
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Blower motor fuse?

Post by Hefeweizen »

The blower on my 1981 6er (E12 based) stopped working and I thought it may be the fuse Problem is that I can't find the fuse that would cover that in the fuse box.
Rainer

1981 633 CSi Project car
2003 330 Xi Daily driver
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Mike W.
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Re: Blower motor fuse?

Post by Mike W. »

It appears it would be fuse 14 on E12 528i's. E24s of course are somewhat different, especially in the heat and A/C with that goofy variable speed blower, but 14 is a starting point. It should be a blue, 25A fuse. Blower motors do die also, either because the bearings seize up or the brushes just wear out. I assume you have tried turning it to full maximum speed? That takes the transistor and related circuitry out of the circuit and connects straight to battery voltage. Except, IIRC they switch the ground, not the hot, the motor should get a full 12V all the time, they then switch the ground side of it.
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter
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Hefeweizen
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Re: Blower motor fuse?

Post by Hefeweizen »

Thanks! Stupid me did not even think about looking in the book! I just looked on the fuse box cover. The fan motor runs great, had it out and bench tested. I rule out anything in the HVAC Panbel since I swapped it out with another one. Of course there is the possibility that the other one is also broken. I'll check fuse 14 tonight! Thanks again!
Rainer

1981 633 CSi Project car
2003 330 Xi Daily driver
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Mike W.
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Re: Blower motor fuse?

Post by Mike W. »

I'm pretty sure when turned to max, it bypasses that circuit board and the big power transistor, a 2955 IIRC.
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter
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Hefeweizen
Posts: 35
Joined: Mon Jan 08, 2018 11:46 am
Location: Colordo Springs
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Re: Blower motor fuse?

Post by Hefeweizen »

Thanks Mike! The PO actually soldered a new, flat fuse in there and the connection was lose. When I bumped into it, the blower started going. Not sure how to get the AC going. It is only the upper fan that runs
Rainer

1981 633 CSi Project car
2003 330 Xi Daily driver
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Mike W.
Posts: 2798
Joined: Wed Aug 30, 2006 12:12 am
Location: Sonoma County

Re: Blower motor fuse?

Post by Mike W. »

Hefeweizen wrote: Mon Sep 25, 2023 6:33 pm Thanks Mike! The PO actually soldered a new, flat fuse in there and the connection was lose. When I bumped into it, the blower started going. Not sure how to get the AC going. It is only the upper fan that runs
It can be done. The '80 E24 I once had was a mess in there, the rotary switch had melted and someone had cut wires and installed a generic 3 speed switch for the heater totally ignoring A/C. It was a challenge to get that going. But there is a microswitch in there actuated off the temp knob that switches things between heat and A/C, along with a couple of relays. I've had that microswitch fail. Seems like I've seen the mounting for it fail too, although that may just be an E12 thing, not E24, I don't recall exactly.
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter
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