OK, Update for today! Found the issue finally. With the dash out I was able to lift the top of the defrost vent up from the dash a little which gave some visibility down through the windshield of the defrost duct door. I did not see anything but realized I could snake a hose down there attached to my shop vac and vacuum the area out. I did this blind but heard something come up my hose. Checked the Mode actuator levers and both now worked perfectly. The small piece of plastic found was from the Old Dashboard. When I bought the truck the dash was broken pretty bad. I plastic welded it back together and put a Dash skin cover on it. It turned out very nice looking but removing the dash skin takes a lot of effort. I still need to put the entire truck back together but it all tested well and all vents appear to work as intended. The upper small mode door lever now moves right at 1" as it was supposed to.
FYI: after full dash removal which included disconnecting the battery to remove the front air bag I hooked up the power after the dash was installed and all the vents worked perfectly, I did do the normal, first put the car in AUTO mode, then turn the key to off, turn the key to ON or RUN position for 2 minutes, turn key off for 10-20 seconds and then turn the key on. Everything working normally. I never started the car for this procedure because I had my battery charger hooked up and running on a 25 amp charge. If I did not have the battery charger hooked up I would have started the engine. Modern cars draw a huge number amps with the key on and engine not running. If the system detects low voltage it puts you into electrical problems on the computer as it senses low voltage while it resets everything. So either use a good battery charger or as first instructed start the engine before doing this procedure to re calibrate the actuators. Hope this helps.
This Suburban had the JVC Radio upgrade added, what a very nice unit, has Apple CarPlay, integrates fully with your Iphone with zero effort, has the DVD player, NAV and an amazing amount of options. Like having a Ipad in your dash. I am not a stereo system guy but this is so much nicer than the OEM versions from that time.
