I have a 2002 Dodge Ram 1500 5.9L V-8 and my airconditioning cools just fine while I am driving but as soon as I stop at a light for any length of time or put it in park it stops cooling until I get moving again.

I have a 2002 Dodge Ram 1500 5.9L V-8 and my airconditioning cools just fine while I am driving but as soon as I stop at a light for any length of time or put it in park it stops cooling until I get moving again.
Have the fan clutch tested. Sounds like it's not working properly.

You could also consider adding an electric fan to help move air across the condenser while sitting still, especially if you live in a high heat/humidity area.