Well, after spending 3 days cussing out GM engineers I finally got all my spark plugs changed yesterday. So today, I decided to tackle adjusting my airbags... Ok, so today I decided to lower the rear height of my 5.3i as the measurement at the front fender wells were 31.5 both sides. The right rear was 34 and the left rear about 33¼. The factory method works just fine... in a way.. After loosening the rear lug nuts, I jacked one side at a time and put a jack stand (up 2 notches) under both sides of the rear axle. Since all I had in small steel stock was a length of thread stock. I made one exactly 4.33" and another 5.33". After removing the rear tires/rims.. Turned on the ignition and waited for 2 minutes for the airbags to settle, then turned off the ignition (if you go longer than 2 minutes, it start adding air again.) The 2nd time I used a kitchen timer; then turned it off just prior to 2 minutes.
After pulling the 2 fuses (Manual say 48 for the body fuse box but it was 49 in my 08 for the 4wd) The Drivers side was right at the 4.33" so I adjust the sensor which was quite a bit off. Going over to the passenger side, it was still about an inch high so I jacked up the side of the car about 6" and dropped it fast. Now it was a bit low .. so I raised the frame a little at a time until it was at the 4.33". Adjusted that sensor. Jacked up each side mounting the tires and removing the jack stands. Put both fuses back in. Measured both at the top of the fender well; both were at 32" (not on the bump stop) front was still at 31.5. Started the car the air pump came on.. when it finished the rear fender wells were still at 32" (Yay!) exactly and not even off a 32nd of an inch. . now that is what I call within tolerances despite what the "Dealers" have told people. About 15 minutes later I took it out for a road test over some rough uneven roads and when I came back the rear measurement were still at 32"! I won't include the Air suspension manual but the picture is of the 5.33" and 4.33" measuring "tools" Oh also between one day of the spark plugs circus I installed a set of the Great LED turn signals of TXBlazer. I'd installed a pair on my previous Rainier but these new ones are even better!