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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Does anyone have a wiring diagram? I feel like I’m missing something here. I need to determine the causation between the removal of the climate control and the now high resistance on the main power wire.

Very frustrating.


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WDS...
https://bmwteka.com/wds/ru/e53

Also handy - for Android: -

https://play.google.com/store/apps/d...wdsviewer.free

WDS shows that the output stage (speed control in HVAC panel - the IHKA ) is between Fuse 64 and the blower motor....

Thank you! Last time I was looking for the WDS I couldn’t find it, this is a big help in removing unknown variables


So here’s the FSR connector:

https://uploads.tapatalk-cdn.com/202...fd6213b9a3.jpg


I’ve tested all 5 pins of the connector. On pin2 I probe 700ohms between X8722 and X10454. While I’m probing I have the 50A fuse removed and have the probe inserted into the spade terminal. I have the X8722 connector disconnect and probing into the female side.

If the wiring diagram is correct then I can only conclude there is a an issue with the wire.

Anyway I’m going to do more testing tomorrow

Thanks again


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Solved the issue by running my own wire from X10454 to X18722. It’s still unknown how the factory wire failed and why it failed when it did but alas I can warm up my frozen toes now. If it wasn’t freezing I would’ve pulled apart the interior. Instead, I decided to cut out the old and solder in a new wire.

https://uploads.tapatalk-cdn.com/202...9941c0eb50.jpg

Thanks everyone for the help!

Cheers, E53Envyy


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good find!

Are you really sure that you are not probing connector X671 and that X18722 isn't the problem?

I’m sure. X18722 is a 2 pin connector located inside the dash almost directly behind the climate control. The connector had no visible damage and I cut and solder my wire in before the connector so the connector can still be used to disconnect power going to the FSR. Basically I’ve replaced the wire going between X10454 and X18722.


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I doubt the problem is in the wire itself. I would make really sure the crimps and connections on the ends of the wire are good before looking at the wire itself.