2003 Dodge Ram 1500 air conditoner trouble when stopped

My 2003 Dodge Ram’s air conditioner works great at speed, however when you stop for very long it starts blowing hot air. After you begin moving again it will slowly start blowing cold air again. Why will it not continue to blow cold air when the vehicle is stopped?

Is the radiator fan working properly. It should go to full speed with the AC on even with the engine cool. In addition to that, check to see that the condenser and radiator are clear of debris.

A low refrigerant level could cause this also as the low side pressure will rise at idle and the high side will drop. At elevated RPMs the reverse will occur.
Since the basic principle behind A/C operation is a pressure drop in the refrigerant, it’s possible that a bit of refrig. loss has dropped the pressures enough so that the previously mentioned drop is not what it should be.

Most units leak a bit of refrigerant over time and since this one is 7 years old it may be time to throw the gauges on it and see what’s going on.

I checked the pressure level on the high side and it starts high and drops to 45 at idle. Also, the fan seems to run at regular pace and there is no debris blocking the fan nor the radiator. Any other suggestions and thanks for your suggestions.

You might clarify this a bit. You state you checked the pressure on the high side and drops to 45 at idle. The high side should never be that low.
What is the low side? Or do you mean that 45 is the low side pressure?

With the engine and A/C off for an hour or so, the system pressure should stabilize and remain the same on both the high and low pressure sides.
Normally this will be around 115-120 PSI. Once operating, the high side will go up to 225-275, depending, and the low around 35-45; also depending.

Sorry, correct, when I hooked the gauge to the low side the pressure would be fairly high and slowing come down to right at 45. The air blows very cold at any speed other than idle. Thanks for your suggestions.