Remove the center cap on one of the wheels and look inside.

At each tire, there is a "T"-shaped fitting attached to the center of the hub. One leg is a tube to the tire, one is threaded into the hub, the third is a common tire valve.

There is a small tab on the side of the part threaded into the hub. This is the "quick release". It does not actually release the fitting from the hub (it takes a 3/4" open-end wrench for that). When you press this tab, the body of the valve will pop out about 1/4". With it in this position, the air channel between the CTIS system and the tire is closed off in both directions.

If part of the onboard system fails, you can use this to isolate the wheels from the system. You should have a yellow plastic coiled air hose that came with your truck. You can use this to inflate your tires from your compressor if your onboard system develops a leak. [You can also use this to inflate tires at a gas station or from any other source of compressed air designed for tire inflation.]

If you leave the fittings pushed in, both tires on that axle are connected together, and can be inflated by adding air through either valve.

If you get a slow leak in one tire, you can isolate the other tire on that axle, then use the compressor to keep air pressure in the damaged tire while you continue to drive (assuming the leak is slower than the air compressor).

Dave B.
www.BlueHummer.com