09 diesel AC issues?

[Sylvan Lake V35]

I have an 09 35d, it's finally warm enough to need AC and I have noticed that unless we are moving the AC shuts off. Is this normal? When we first start the vehicle it blows hot air until we get driving and at a stop light the AC will shut off and blow cool/warm air and you can smell that the AC is off.
I am just not sure if this normal I know every other vehicle I have had the AC pumps cold even when I start it up and at lights.
Another note the temps have only been 20-24deg celcius....slightly above room temp but the black truck is likely closer to 30deg after sitting in the sun. My local dealership is a 1.5hr drive and it takes about 2 weeks to get in so I want to be sure there is an issue before I go through that hassle.

Thanks guys.

[Sylvan Lake V35]

Oh sure everyone replies in the other guys thread not mine my issue seems slightly different...anyway my warrantee expires on the 28th so I am just taking it in.