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AC blowing warm with ticking noise coming from dash.

5633 Views 4 Replies 4 Participants Last post by  bmwpower
Dealer says the system is charged, clutch is working, and system is functioning. I hear this ticking noise coming from dash and took this video of the noise from the driver's side footwell looking at the center stack just above the kick panel:

Any idea what is wrong? Is it the actuator?
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Oh man, are you in trouble! Nah, just kidding. Yes, it looks like the servo motor for the airmix door has lost it's mind, so it's cycling between heat from the heater core and cool air from the evaporator. Whether the van appears to have manual controls (CE / LE) or automatic (XLE), the whole system is electronic - there are no cables or hard connections between the dash and the HVAC hardware. A servo motor is supposed to track the setting on the dash, but they can go bonkers. Most likely it's the actuator/sensor in the motor assembly. In an extreme case it could be the AC Amplifier and ckt board in the dash. In most cases, simply swapping out the motor assembly (removing the 3-4 retaining screws and carefully disengaging the cam rod) is all it will take.

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Oh, had a thought tonight about something worth trying before you tear it apart. Sometimes servomotors hunt because they have lost their Zero or Home Position reference. Try turning the temp control all the way to hot, leave it there for 10 seconds, then slowly turn it all the way to cold (move it from hot to cold over a period of 10 seconds). Repeat the other way (cold to hot), then turn it where you want and see if it goes and stays there.
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