Blower Regulator Control
WARNING: This page is about a different car, the 2001 Mercedes-Benz SL500 and 2000 Mercedes-Benz SL500. However, it is still accessible from the selected car via links, so may be relevant.
Connect appropriate test cable to A/C push button control unit right harness connector. See CONNECTING TEST EQUIPMENT under SELF-DIAGNOSTICS. Ensure A/C push button control unit is connected to test harness. Connect voltmeter negative lead to socket box terminal No. 19 and positive lead to terminal No. 1. Turn ignition on. With blower motor speed set to maximum, voltage should be more than .5 volt. With blower motor speed set to minimum, voltage should be more than .7 volt. If voltage is not as specified, possible cause is wiring harness failure or blower motor failure.