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View Full Version : Blower motor not working, when in car but works when hard wired to a battery


bimmerred535i
10-16-2009, 05:44 PM
7/89 build date e34 535

Problem: My blower motor blew, and I replaced it with another used blower motor that ran well for about 3 or 4 months, and then it too died (but works when hooked to an external battery).


What Ive tried:
I have tested the car's leads to the blower motor and they read 12V, then I hard wired the blower motor to a 12V external battery and the motor works. I have two used blower motors that I tried this to and they both work.

I have been reading through the archives and trying to see if anyone has the exact same problem as mine, but most say that they have problems with just the fan speed (resistor/sword) and not with the motor not running at all.
Tiger
10-16-2009, 10:44 PM
Sword... they do die and yet the motor is still good. Your car doesn't have the resistor pack like the later model would have.
Blitzkrieg Bob
10-17-2009, 01:59 AM
Usually when the sword goes, you can still get the high fan speed.

How's the fuse? mine has popped a few times
bimmerred535i
10-22-2009, 10:36 PM
I pulled the sword out tonight and was tried to see if anything looked fried....It seems that one of the Mosfets has melted the gold external coating.....Ordered a board from vines auto ($75) im a bit too lazy to tear it all apart and dont have the time. Plus Ol' man winter is knockin in Ohio. Hope this solves it....Thanks for the suggestions
Asamaan
10-28-2009, 11:13 AM
I have the resistor pack not the sword, but I had mine work on 4 only even with the new resistor pack. I ended up replacing the fan switch on the dash and it worked perfectly fine after that. So I would also check your fan switch.

good luck
Al
91 535iA
Ferret
10-28-2009, 11:43 AM
I have the resistor pack not the sword, but I had mine work on 4 only even with the new resistor pack. I ended up replacing the fan switch on the dash and it worked perfectly fine after that. So I would also check your fan switch.

good luck
Al
91 535iA

If you search back under my name there's a repair guide I put together for the switch a long time ago.
bimmerred535i
10-28-2009, 03:41 PM
If you search back under my name there's a repair guide I put together for the switch a long time ago.

I bought a remanufactured sword from vines auto for 75 and it solved my problem. Thanks for the info though as I will fix my broken sword and throw it on the shelf.