Mechanic question - Buick A/C

[Freshly Minted Georgian!]

I love my trusty old '02 Park Avenue but it has one vexing little problem. Most of the time air blows out the defrost vents primarily. I don't think it's the blend door actuator because if I unplug the battery for a few hours it starts working again. I suspect it's a problem with the body control module, purely electronic. I have two questions really.

1) What do you think of my theory?
2) If it IS the body control module, without crawling under the dash (apparently it's located behind the glove compartment) to pull the actual model number to find the right replacement, is there any way by using the VIN to determine which BCM modules are compatible?

 

[moosensquirrel]

You probably have a vacuum leak. I once had rats chew up some tubing from vacuum source to the distributor/diverter...the valve that directs where the air comes out inside the car: default is defrost on many cars. Check the tube connections near the heat/AC blower.

 

[Freshly Minted Georgian!]

If it was just a vacuum leak (which I've thought of) it wouldn't be corrected by unplugging the battery. It's been this way for a while, I've been researching it for a long time!

 

[Kyzrsoze]

Does it have a standard a/c panel or does it have climate control with a temperature setting?

 

[Freshly Minted Georgian!]

climate control. Those older Buicks were notorious for bad quality soldering on the components in both the climate control module and the instrument panel. I've long since taken both apart and sure enough, not only were there some bad solder joints that had cracked, there were some components that we flat out NOT soldered at all. You'd find one leg of a resistor soldered and the other just sitting in a PCB through hole with no solder whatsoever. I got both the climate control and the instrument panel taken apart and properly soldered a few years back.

 

[Kyzrsoze]

climate control. Those older Buicks were notorious for bad quality soldering on the components in both the climate control module and the instrument panel. I've long since taken both apart and sure enough, not only were there some bad solder joints that had cracked, there were some components that we flat out NOT soldered at all. You'd find one leg of a resistor soldered and the other just sitting in a PCB through hole with no solder whatsoever. I got both the climate control and the instrument panel taken apart and properly soldered a few years back.

I'd still start by replacing that first, even if you had it repaired previously.

 

[Freshly Minted Georgian!]

Well, that's certainly easier to get to than those darn BCMs! I'll poke around and see if I can find a replacement.

 

[Freshly Minted Georgian!]

it IS working properly right now, had the battery out over the weekend to replace it and when I put in the new battery everything was working properly again.

 

[tas6691]

PRESS
OFF AUTO & RECIRC buttons for 1 second...should read codes that are in BCM
My bet is on B1344 mode door movement fault.
Probably either the control head or mode actuator, BCM just monitors the system doesnt control mode or temp movement...control head does that

 

[3clicks_Off]

Every pull-a-part yard I've been to has a computer program that cross-references for compatibility and they always tell me which vehicles have that part and print out where the vehicles are in their yard.