Diesel Data: Automotive Repair

Test I

PINPOINT TEST I: THE SUBWOOFER IS INOPERATIVE


Test I1-I2:






Test I3-I5:






Test I5-I7:






Test I7-I9:






Normal Operation
The subwoofer speakers are powered from a separate subwoofer amplifier. The clip detection circuit, 7-MD19 (YE/RD), carries out two functions: to turn on the subwoofer amplifier, and to indicate to the audio unit when the subwoofer output distortion signal reaches a damaging level. The audio unit then reduces the audio output signal to the subwoofer amplifier.

Possible Causes
- subwoofer amplifier
- subwoofer speaker(s)
- audio unit
- circuit 1-MD19 (WH/RD) open or short to ground
- circuit 2-MD19 (GY/RD) open or short to ground
- circuit 7-MD19 (YE/RD) open or short to ground
- circuit 8-MD21 (WH/BK) open or short to ground
- circuit 8-MD23 (GY/BK) open or short to ground
- circuit 10-MD21 (GY/BK) open or short to ground
- circuit 10-MD23 (WH/RD) open or short to ground
- circuit 30-MD19 (RD/BU) open or short to ground
- circuit 31-MD19 (BK/BU) open