. . . no relationship
Not sure about your car, but on my S500, the external temperature probe has no relationship with the A/C temperature and/or its operation. It's only gives an indication of the outside temperature to the LCD panel in the instrument cluster.
My probe is mounted in the left front bumper below the main section. Because the probe is mounted so close to the ground, it tends to read high because it 'reads' the hot pavement temperature.
The A/C uses a separate coolant sensor (B10/8 on the top of the manifold) to control its operation. I believe your dealer is correct.
It sounds from your description as though the LCD panel has an intermittent connection.
Regards . . . . JimF
'94 S500 Cpe
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