My fan is constantly on and my climate control panel looks dead
 

Hopefully someone can help me with this issue on my E53. My AC/Heater is constantly blowing even when the car is off. The climate control panel doesn’t light up and none of the buttons work. I’ve removed fuse 48 to stop the air conditioning constantly blowing. I replaced the FSU/FSR as that’s what I read was almost always the issue. I also ordered a second hand climate control panel off eBay just in case but it turns out my panel is 18 pin and the new panel is 12 pin. Oh well. I guess there is no way to use the 12 pin panel? It looks expensive to get an 18 pin panel. Do you think if I get an 18 pin panel that will solve the problem or is the issue likely elsewhere?

Well crap. I saw the title and was thinking AUX fan and that you should trade with UPgrayd [emoji1787]

Andrew is the guy who can help you. He lives and breathes circuit issues.[emoji106]

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Is the aux fan on fuse 48? When I drive it still kicks out hot air through the vents even though I have pulled fuse 48. The FSU/FSR was awkward to get in. Maybe it’s not seated right. Would that cause the panel to still be dead? I kind of think the panel would not be dead if it was just the resistor but I really don’t know anything about how the system works. That’s why I got the panel off eBay as it always felt to me like the panel could have died rather than the resistor.

Failed AC control module (IHKA). Final stage would not explain dead IHKA display.

One thing that could explain this is poor connection between IHKA front panel and actual board. (I encountered this once while cleaning the IHKA internal fan. One of the pins between front panel and board had poor connection; front panel was dead and blower was constantly on.)

Not really sure what you mean by 12 vs. 18 pin panel.

Fuse F48 is Terminal 30 (continuous voltage) supply only for IHKA.

Ram air will still push some air in and water valves are open on rest state so max coolant flow to heater core.

Sorry I meant that the black connection on the panel I have is 18 pin. There is a 12 pin version too which is what the replacement panel I got off eBay has. I’m not sure what difference is but the panel is from a 2003 or 2004 car but mine is a 2002 car.

Occasionally on my E46 my IHKA would run the fan even with the key off. I would just pop out the IHKA and remove the large connector and reconnect it and it stopped running. Did this 2 or 3 times and it stopped happening. Very strange.

I'm leaning towards trying to check the connections on the panel and possibly fixing it. Are there any obvious failure points that I should look out for?