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After changing battery, air won't blow out vents, only floor and defrost

I only have 62000 miles on this thing, and I’m about ready to take it a junk yard. The driver power window switch won’t work, but Buick states there is a pending recall, inside the panel, the switch is melted. My battery went dead on me a couple of times and I got it jump started. I went and got a new battery and now the vents won’t blow. What is wrong with this stupid thing. (2006 Buick Ranier)
Thanks

Donate it to charity and take the tax deduction.

I believe that you have an electronic automatic temperature control on this Rainier. Floor and Defrost position is probably the default setting. There is a possibility that you blew out your Heater A/C & Blower Control Module. It’s a common problem on the 2004-2006 Rainiers. Have it checked out by a good, independent mechanic.

The Body Control Module probably lost it’s adaptive memory when the battery was disconnected. If so, the module needs to go thru a relearn procedure or needs to be reprogramed using a dealer scan tool.

This explains what can happen to computers/modules when the battery is disconnected on some vehicles. http://www.aa1car.com/library/battery_disconnect_problems.htm

Tester

This is a common problem with this series of vehicles. When you disconnect your battery and reconnect it. The HAVC system goes through a reset procedure. You may have heard it when you reconnected the battery. It makes a loud clicking noise. This is the actuators in the HAVC system doing a rest. Problem is if you have a weak actuator it will strip the plastic gear and now the actuator won’t go to the proper setting. The actuator is fairly cheap. But the change is a PITA. The dealer will charge you a small fortune to change it. Do your self and save money. Just use patience when doing the job and everything will be good. Thank GM for this lovely design.

On a tb forum I go to this is not an unusual problem, and for whatever reason if you do not use a memory saver you end up replacing actuators.

While I’m not familiar with the Buick Ranier to even the slightest of degrees I might pose a theory as to why the actuators break.
The older Lincoln Marks with EATC had a tendency to break blend door arms which are made of plastic and no doubt similar to the Ranier in some way.

The EATC on the Lincolns have a low setting of 60 and a high of 90. I always keep mine set on 65 or 85 as that extra 5 degees appears to put a bit too much of a pull on the plastic arms with the blend door hitting the stops on either end of the temp spectrum.
As an analogy, think of a household door that won’t quite close and you keep forcing it until the door handle breaks off.

With the Buicks, maybe the changing of a battery causes a voltage surge or electronic hiccup which causes the actuator to exert a bit more than it should.
That’s just a theory anyway which may have some truth to it or may be totally misguided. :slight_smile:

Before panicking, I’d disconnect the battery again, wait 15 minutes and reconnect to see if this resets the module. There may also be a reset/test mode you can access by pushing a combination of buttons on the climate control. I used to have to do this on my old Chrysler a few times a year before I replaced the climate control module. Look online for a reset procedure, or call a dealer and ask a mechanic how to do this. If they refuse to help without you bringing it in, call a different dealer. There may also be a service manual for your Buick that is available cheaply on ebay or similar, and this may tell you how to reset it. Good luck.

@OK4450-

maybe the changing of a battery causes a voltage surge or electronic hiccup which causes the actuator to exert a bit more than it should.

You had it right with your door analogy. The actuator reset process drives the actuator to the extreme positions to recalibrate the controller. The problem occurs when the controller keeps driving it past the end stop and doesn’t detect it’s there. The design is poor and often results in damage to the plastic gearing.

If it is the blend door here is a replacement discussion about what happens and how to replace it with pictures:
http://www.sparkys-answers.com/2009/05/2003-gmc-envoy-no-ac-vent-control-b0263.html

I used this site to make one work in my mother-in-law’s Envoy and I only unplugged the defective module and manually forced to to blow out of the vents. We haven’t gotten around to replacing the module yet.