Your car requires a little different procedure to read the operating parameters.

To read the operating values, do the following;
1. IGNITION : Position 1
2. Press the AUTO button
3. Set both temperature selectors to 72 degrees F.
4. Press the REST button for more than 5 seconds.
5. The left display will alternately show the number "1" and the in-car temperature.
6. Press the AUTO button and the next component number and its value will be displayed.
7. Press the REST button to end the test program.

Start there first. The important readings are #5 and #7 at least to see if it's operating.
#5: Evaporator Temperature Sensor (B10/6) shows the air temp at the vents; should be 40F or lower depending on the outside temperature.
#7: Refrigerant Pressure in Bar. For a properly loaded A/C system you should see around 7 - 9 bar; on a HOT day, in traffic, it can go to 15 bar. Moving should bring it down. (1 bar = 14.7 psi)

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Regards . . . . JimF
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'94 S500 Cpe

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