Let's play a game - diagnose my E46 AC problem

[Terri Kennedy]

Originally Posted by rumatt

Sometimes there are issues with fan speed. The auto mode just doesn't boost the fan as high as is needed, so I turn the thermostat from 70 down to low 60's... The fan kicks up and it gets nice and cool.

Yesterday the air being blown wasn't cold. I lost all cooling and it was blowing warm air. I had to ride the rest of the trip windows down.

The FSR only affects fan speed (and it hasn't been an actual resistor in years - it is a Darlington transistor array).

This could be a large number of things, but I suspect the IHKA (Irritating Heating Kooling Artifact, according to Tech Talk, who prefers manual controls) based on the combination of incorrect fan speed and random un-requested changes in temperature. Other possibilities are the duct flap actuators or something in the refrigerant system (low gas or bad clutch, as mentioned elsewhere).

I have a pre-coded E46 IHKA if you want to borrow it to see if things get better. You need a coded one because the ones you get from the parts counter sit there completely useless, displaying "NC" (Not Coded). Coding just tells it if it should operate in degrees C or F mode and if the car is a diesel or not (the "bad air detector" that auto-switches to re-circulate is disabled on diesel cars).

[Terri Kennedy]

Originally Posted by Terry Kennedy

I have a pre-coded E46 IHKA if you want to borrow it to see if things get better. You need a coded one because the ones you get from the parts counter sit there completely useless, displaying "NC" (Not Coded). Coding just tells it if it should operate in degrees C or F mode and if the car is a diesel or not (the "bad air detector" that auto-switches to re-circulate is disabled on diesel cars).

The aforementioned IHKA:



64-11-6-956-319 US MSRP $832.62, GetBMWParts $679.42.