Coolant Temperature Gauge Test
- Remove 4-terminal connector from temperature gauge sending unit (located on cylinder head coolant flange). See Fig 1
. Sending units terminal numbers are molded into connector plastic. Connect Variable Resistance Tester (VW 1301) between terminal "T" (Brown/Black) lead and ground. Turn ignition switch to ON position. Set dial of tester to following numbers and check gauge readings.
- With dial set at 660, gauge should read cold (between 2 dots). With dial set at 50, gauge should read hot (between 2 dots). Keep tester connected for a minimum of 2 minutes to allow gauge needle to reach checking points. If not within specifications, check voltage supply and voltage stabilizer. If voltage is found within specifications, replace gauge.
- To check voltage supply, Remove connector from temperature gauge sending unit. Attach voltmeter between Terminal "+" (Black/Blue) lead and ground. Turn ignition switch to ON position. Voltmeter should read approximately 10 volts. If not, pull instrument cluster out and check for voltage at 26-pin connector.
- Attach jumper wire between terminal "C" (Blue/Yellow) lead of temperature gauge sending unit and ground. Turn ignition on. Overheating warning light should flash for 30 seconds. If light does not flash, check bulb. If bulb is okay, repair open circuit. See chassis wiring diagram in appropriate WIRING DIAGRAMS section. If wiring is okay, replace instrument cluster printed circuit board.
Courtesy of AUDI OF AMERICA, INC.