Can't put air in the rear tires WTF
 

I got new Continental DWSs last fall and they also installed new sensors.
I went to check the tire pressures and decided to add some air all the way around. I was able to get air into the 2 front tires but it wouldn't go into the rears. I pressed the air hose into the valve and nothing happens. WTF is going on here? Its like the air is blocked by something.

If you press on the pin inside the valve stem, does the air come out of the tire?

Your Schrader valves could be either stuck (unlikely) or too far down in the stem.

That's a new one on me. I can't imagine two valves failing at the same time. Not impossible but highly improbable. As per cooltoy, press on the valves (you may need to use a small screwdriver or similar) and see if air leaks out. If you get air out, the valves are good and I have two guesses:
1) The stem on the sensor is too short and you are not getting a good fit with the air chuck because of interference with the wheel.
2) Like Fountainhead says, the Schrader valves are too short and the tip on the chuck is not pressing on the valve.

Have a professional air installer take a look at it.........





but seriously, just take it to a shop and see if they can put air in it for you. If they can't do it, then you can worry about what's the next step. Our core removers at Costco click after a certain pressure (15 in/lbs?) to avoid over tightening.