I have a 2000 Suburban 1/2 with the 5.3. One day last week when I left to go to work I noticed that the tow/haul light was on after I pulled out of my driveway. At the time I just assumed that I had accidently hit the button.But from that point on every time I start the engine the light comes on and I have to manually turn the OD back on. By default it should be on and have to manually turn it off. I have noticed sometimes that if I put it in reverse first that the light is not on but as soon as I put it in drive it comes on. A while back (maybe a year ago) I noticed that I would have to put the gear shifter towards me while pressing the button to turn the OD off. I assumed that there was a short in the switch or wiring. But this is beginning to worry me. a couple of days later it got really warm so on a short trip I turned the ac on but was not able to change the vent position from defrost to vent. No matter what position I would put it on the ac would only blow from the defrost outlet. Even the rear ac will only blow from under the seats. . I have gone thru the fuses but was not able to find any blown. I don't think the two problems are connected, but it seams strange that they both happened. I just don't know if they happened simultaneously. My Father-in-law purchased this truck new in 2K. He had to have the transmission rebuilt in 05. I purchased it from my wife's sisters in 06 after he passed. The truck has been meticulously cared for and even though it is showing it's age I want to keep it mechanically sound.Has anyone ever had had this happen to them? Any advise would be appreciated.