I have a 2000 Suburban 2500 LT with about 175K miles. When I bought it, the AC would only come out the defrost vent and the guys said it was a mode door actuator issue and actually had the part from NAPA which was installed with no problems. However, the Mode dial works in reverse. The Defrost setting blows out the front vents and the front vent setting operates the defrost. The bad thing is I can not get any air(heat) to come out to the foot vents. When I turn the dial to straight up and down it only blows out the defrost or front vents. No foot air again. Just curious if anyone has experienced this. I hve the original mode door motor still, but the part number is hard to read. It looks like 93313334a or 83313334a. Just curious if I should try a new motor or if it might be something else. Any thoughts?