I have a 99 E320 base that runs cold AC when it wants to. You can hear a click when the compressor kicks in but when it doesn't run there is no click under the hood. It seems to run fine when the weather is cooler (under 85 degrees). Is there a solenoid or relay switch past the dash control panel that activates the compressor? There is no leak anywhere and the system is full of Freon. Please help.

 

could be overfilled, should take about 2.2 lbs,