2003 Yukon XL Denali - Rear AC wigging out

I have a (see subject) and the rear AC is really wiggy. I thought it was completely shot at one point, so I checked every fuse I could find. They were all fine. I went without AC for a few months (rather,
my kids did) and one day out of the blue, I take a corner, hit a pothole, and FOOOOOOOOOOOO the rear AC was blaring (i had the dial all the way up). Another bump, and it's off. But it's not limited to bumps. Sometimes it will just turn on while I'm taking a corner, and then shut off for no reason. Where's a good place to start checking for a problem? I already took the control panel off the roof and verified that everything's wired properly (no loose wires).
Thanks in advance.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
there is a main ground for the rear a/c behind r/rear quater pannel/if you remove the side panel you will see the a/c control box assembly,look torwards the front their should be a ground wire attached to the body if it was loose you could have this problem, hope this helps, also try wiggling all harness you see on the hvac module
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

where exactly is the r/rear quarter panel?
thanks
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
the right rear quarter pannel is the plastic inside cover that runs along the far rear passenger side/if you open the back lift gate and look to the right that entire plastic section comes off,1st-remove,upper&lower entry trim,remove the right plastic cover along the far back pillar (has small speaker in it)all these covers pull off with no screws exept the large quarter pannel it has one screw near the front 7mm/and the black plastic odd looking hander at the rear unscrews as well.with rear gate open look to the right,about mid way down you will see this circular piece you may need pliers to break it loose''hope this helps-you will need to pull with some force for panel removel gm makes good retaining clips!!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Okay, I've popped off the panels, wiggled/tightened everything I could find, but that still didn't help the problem. Are these the right things? (pics linked)
http://www.wootlands.com/myk/panel1.jpg
http://www.wootlands.com/myk/panel2.jpg
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
yes those are correct/B is tha main suspect if you are looseing every thing ie. temp and fan control/B- is your main rear hvac control module/ Gm has had some issues with these and the new ones are updated/take down the part number and verfie by calling youre local dealer parts dept to see if part number superseds to a differnt one/C- controls temp and (A) controls vents hope this helps/Russ..
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
well, wouldn't ya know it? you're a gmc genius. i smacked B and everything kicked on. i power cycled the truck a few times, then it eventually stopped working again. i'll call the dealership and ask them about the part. thanks for all your help :D
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
thats cool!!pardin the pun,,hehe Im glad to have helped,actualy i work for gm and wish they all went that smooth..feel free to ask anytime/russ
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.