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Test Procedure

WARNING: This page is about a different car, the 2001 Audi S4, 2001 Audi A4, 2000 Audi S4, and 2000 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Ground connection for test procedure is available at connector "D" terminal No. 14 or 15.
  1. Using Adapter Cable (VAG 1598/12) and DVOM in 20-volt range, check voltage between adapter cable terminals No. 9 and 14 with ignition on. Ensure battery voltage exists. If battery voltage does not exist, check Black/Red wire between fuse block and A/C-heater control panel. Also check Brown wires between A/C-heater control panel and ground. See WIRING DIAGRAMS  .
  2. Check voltage between Adapter Cable (VAG 1598/12) terminals No. 9 and 15 with ignition on. Ensure battery voltage exists. If battery voltage does not exist, check Brown wires between A/C-heater control panel and ground.
  3. Turn ignition off. Using Adapter Cable (VAG 1598/11) and DVOM in 200-ohm range, check resistance of circuit between ground and adapter cable terminals No. 49 and 52. Ensure resistance for each circuit is less than 20 ohms. Repair ground circuit(s) if necessary.
  4. Connect Adapter Cable (VAG 1598/11) to A/C-heater control panel. Connect LED Voltage Tester (VAG 1527B) between adapter cable terminals No. 15 and 33. Turn ignition on. LED should illuminate. If LED does not illuminate, repair open or short. See WIRING DIAGRAMS  .
  5. With Adapter Cable (VAG 1598/11) and LED Voltage Tester (VAG 1527B) still connected, start engine and allow to idle. LED should flicker briefly (time signal) and then illuminate. If LED does not flicker, check signal from instrument cluster. Repair as necessary.
  6. Using Adapter Cable (VAG 1598/11) and DVOM in 20-volt range, check voltage between adapter cable terminal No. 7 and ground with ignition on and parking lights on. Voltage should be 0-12 volts depending on illumination rheostat setting (instrument panel illumination dimmer switch). If voltage is not as specified, repair open or short in Gray/Blue wire.
  7. Using Adapter Cable (VAG 1598/11) and DVOM in 20-volt range, check voltage between adapter cable terminal No. 7 and ground with ignition on and parking lights off. Voltage should be approximately zero volts depending on illumination rheostat setting (instrument panel illumination dimmer switch). If voltage is not as specified, repair short to battery voltage in Gray/Blue wire.
  8. Using Adapter Cable (VAG 1598/11) and DVOM in 20-volt range, check voltage between adapter cable terminal No. 45 and ground with ignition on and parking lights on. Voltage should be 0-12 volts depending on square-wave signal from instrument cluster (DVOM will indicate average voltage). Brightness of A/C-heater control panel display is determined by length of activation. If voltage is not as specified, repair open or short in Gray/Blue wire. See WIRING DIAGRAMS  .
  9. Using Adapter Cable (VAG 1598/11) and DVOM in 20-volt range, check voltage between adapter cable terminal No. 45 and ground with ignition on and parking lights off. Voltage should be approximately 0-12 volts depending on square-wave signal from instrument cluster (DVOM will indicate average voltage). Brightness of A/C-heater control panel display is determined by length of activation. If voltage is not as specified, repair short to battery voltage in Gray/Blue wire.
  10. Using Adapter Cable (VAG 1598/11) and DVOM in 20-volt range, check voltage between adapter cable terminal No. 46 and ground with ignition on and parking lights on. Voltage should be approximately battery voltage. If voltage is not as specified, repair open or short in A/C-heater control panel ground circuits.
  11. Using Adapter Cable (VAG 1598/11) and DVOM in 20-volt range, check voltage between adapter cable terminal No. 46 and ground with ignition on and parking lights off. Voltage should be less than 2 volts. If voltage is not as specified, repair open or short in A/C-heater control panel ground circuits.
  12. Using Adapter Cable (VAG 1598/12) and DVOM in 20-volt range, check voltage between adapter cable terminals No. 8 and 14 with ignition on. Voltage should be approximately battery voltage. If voltage is not as specified, repair power supply or ground circuits. See WIRING DIAGRAMS  .
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