It probably means you're a little low on your refrigerant charge.

 

Running approximately 35 lbs. Which is what it calls for.

 

Is there a valve that controls the flow of coolant to the evaporator?

 

Your evaporator is telling you otherwise, listen to it.

You need BOTH pressure readings in order to have anything useful. A single low side reading is ambiguous.

 

The refrigerant has to flow through the orifice tube which regulates the rate at which it enters the evaporator.

 

Gave up and took my truck to a shop. It had a half pound of coolant in it. That's it. So you guys were right. As far as the heater issue goes I have no idea what is causing it. Heayer core appears to be working correctly. That's a totally different problem at this point. Guess I will worry about it come winter. Thank you all for your input.