Blower fan stopped working after cleaning climate control temperature sensor
 

Hi guys,

Long story short: I removed the climate control to clean the internal fan and temperature sensor. It’d been buzzing away since I bought the car. I reinstall the climate control and now I have no blower fan (but hey, the little fan in the climate control is basically silent now!).

I’ve tested:
- all buttons on the Climate control work and I can audibly hear the vents moving and rear defrost.
- backlight works along with the display
- checked connections and fuses (fuses 34, 64)
- disconnect the battery for 15 seconds and reconnect.


Interesting part to note is when I disconnect the black connector on the climate control the rear passenger fan blows on max.

Anyone have an idea of the issue? I feel like I’m missing something obvious. I didn’t have any issues with the final stage resistor prior to cleaning the climate control but my symptoms point to a faulty resistor.

Any ideas would help! I had plans for tonight but without the defroster I’m kinda SOL


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Using BMW scanner I couldn’t find any codes


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This can happen if one of the pins between IHKA front panel and circuit board is bent during installation and not having contact.

Ok thanks I’ll take a look. Is it fixable?


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Ok, I opened it back up and the last pin was bent :( damn, I was being very careful when reassembling to make sure that would not happen.

I straightened it and instead of pushing the front display onto the housing and circuit board together I first alighted the pins into the display with the circuit board outside of the housing, then slid the circuit board and front display together into the housing.

Anyway, it’s back in the car and still no dice on the blower motor


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Back probe the pin with a voltmeter. Does it show power?

Hi guys,

I’m having an interesting situation. I’ve been probing the final stage resistor connector and believe I found the issue. I can successfully probe the 12v battery source but I’m unable to draw any current. I am reading battery voltage on the pins but I cannot power a test light and I can even directly short the pins together.

I jumped the blower motor with an external power supply and it works fine. I swapped the FSR with a good known working unit and even tested the x5’s FSR in the 330 and it works fine. The climate control signal acts as it should ranging from 2.25-7.5v. I even tried bypassing the FSR completely by jumping the 12v power pins into the blower motor pins and nothing happened… not even a spark.

Overall everything seems to work expect for the main power input into the FSR. Any ideas?

Thanks



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Check the grounds?

Sounds like a high resistance joint somewhere in the supply line - such a joint (connection) will give full voltage until you draw power, then the voltage will fall as the current increases.

This is called "ohms law". ;)

Blower fan stopped working after cleaning climate control temperature sensor
 

With continued trouble shooting I’ve determined that there is 700ohms between fuse 64 (50A) and the blower motor. In an attempt to trace the wire back to the glove box fuse panel I’ve found one connection located behind the climate control. Probing this connection still results in 700ohms of resistance. After the connection the wire changes color from yellow/green to red/green and I believe it joins the main center console wiring harness which runs to the trunk. I guess the next step is too remove the center console to confirm the wire actuall runs to the trunk as that seems counter productive


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