Continuing Blower Issues

ThomHart · #1 08-05-2020, 06:51 PM

Got the fateful smell of burning electronics in my cabin and sure enough, the fan started working erratically. Was reasonably certain it was the blower resistor and found a new OEM one for $50 on eBay. Car was going in for a few things that were out of my scope of capabilities (I'm riding out the apocalypse at my beach house in SC with just a few simple tools) so I asked them to diagnose the fan while it was in the shop. Confirmed resistor, P/N 64116923204, needed to be replaced which the dealer wanted $600 for. Declined the work and once the car was home pulled glove box and trim, installed new resistor but nothing, no fan action. Checked fuses, all good. System seems to work otherwise, A/C kicks in. Checked connector was on correctly and all the way in, all good. Anything else to check or reset? Maybe I got a bad resistor? Was a reputable seller and part looked new. As always, advise would be appreciated.

Effduration · #2 08-05-2020, 08:22 PM

I thought the smell of electronics and blower malfunction was more of an indication of a blown blower motor.

You should try and test the blower directly. Here is a write-up on the the E39, but look around for a write-up on how to test the blower on an e53.. I have replaced the blower on an E39 and sure would rather not do it if I don't have to.

https://www.pelicanparts.com/BMW/tec...or_Testing.htm

wpoll · #3 08-05-2020, 08:36 PM

Yeah, something took out your "resistor" - these things don't normally burn out/smoke up like that for no reason - so the blower motor is also suspect.

PS. I used the term "resistor" since it isn't actually a simple resistor - the FSR (as it is incorrectly known) is a solid state device that controls the blower motor speed.

I hope it's not the blower motor - hopefully it's just a cooked connector or wire.... but something drew a large mount of power....

andrewwynn · #4 08-05-2020, 09:19 PM

My wife's blower would run two minutes then stop. the FSU was so hot it burned me so I swapped with mine to see if the problem would persist.

It did. So I figured blower motor puking too much current and overheating the FSU. Oops forgot need to put the FSU into the air stream to cool the hedgehog. Since I did that worked fine.

So now I'm confused

Put her FSU into MY car to try to confirm was FSU and of course now BOTH are working ok. But the outside temp has dropped 20F so I have to wait until it's hot again to determine blower or FSU.

I plan to get a reading of A on the two blowers. If as I originally suspected wife's is pulling too high of current I will install the new blower coming Saturday.