LEMON Manuals: Even more car manuals for everyone
Home >> Mercedes Benz >> 1998 >> C43 >> Repair and Diagnosis >> External Pages >> Different car >> Section 40 (Manual A/C-Heater Systems - Ml 320, Ml 430 & Ml 55) >> System Tests >> Electrical Tests >> A/C Button

A/C Button

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2001 Mercedes-Benz ML55, 2001 Mercedes-Benz ML430, 2001 Mercedes-Benz ML320, 2000 Mercedes-Benz ML55, and 2000 Mercedes-Benz ML430. However, it is still accessible from the selected car via links, so may be relevant.
  1. Connect socket box to A/C push button control unit and wiring harness. See CONNECTING TEST EQUIPMENT  . Connect voltmeter positive lead to socket box terminal No. 10 and negative lead to terminal No. 9.
  2. Turn ignition on. Depress A/C button switch to on position and set blower speed knob to position No. 4. Ensure A/C button indicator is illuminated. Voltage should be less than one volt. Depress A/C button switch to off position with A/C button indicator not illuminated or set blower speed knob to off position. Voltage should be 11-14 volts.
  3. If voltage is as specified, go to next step. If voltage is not as specified, check A/C button wiring harness circuits. See WIRING DIAGRAMS  . Repair as necessary. If circuits are okay, replace A/C button switch.
  4. Turn ignition on. Depress A/C button switch to on position and set blower speed knob to position No. 4. Ensure A/C button indicator is illuminated. Connect voltmeter positive lead to socket box terminal No. 4 and negative lead to terminal No. 9. Voltage should be more than 3.0 volts.
  5. Connect Fused Jumper Wire (124 589 37 63 00) between socket box terminals No. 4 and 11. Depress A/C button switch to on position and set blower speed knob to position No. 4. Ensure A/C button indicator is illuminated. Measure voltage. Voltage should be less than one volt.
  6. If voltage is not as specified, check A/C button wiring harness circuits. See WIRING DIAGRAMS  . Repair as necessary. If circuits are okay, replace A/C button switch.