94 Lesabre AC switching on/off fast

[vermontcc]

I have this problem

The compressor cycles rapidly on and off only while driving. (40 to 60 times/minute)
This causes the car to feel like it is running rough and surges as the unit engages and disengages.
The cycling does not continue while in park.
It is more prevalent when the AC is set to MAX
I have very cold air at all times
I have had the Freon level checked and a complete servicing of the system done.

I think the controls ystem for turning the unit on and off is at fault.
Perhaps a solenoid or the mechanism that tells it when to turn on.
I hope it is not the clutch on the compressor.
My mechanic and the dealer have been no help.( If it is not doing it when it is in idle they can’t seem to get a clue)

I was hoping y’all understand this better than the “experts”

[HotZ28]

You have a switch in the low pressure side of the system which opens at about 24 PSIG, cutting off the compressor. The evaporator warms up, and when the pressure reaches around 40 PSIG, the switch closes again, restarting the compressor. This method causes a lot of wear and tear on the compressor clutch. You could have an overcharge of Freon, or a bad low side switch. It would be best to have someone check your high and low side pressure. Do you know if it has R134a in the system?