Diesel Data: Automotive Repair

Test Q

PINPOINT TEST Q: ONE TURN SIGNAL LAMP IS INOPERATIVE


Test Q1-Q2:






Test Q2-Q3:






Test Q3-Q5:






Normal Operation
Power is supplied from the central junction box (CJB) to the LH front turn signal lamp through circuits 29S-LF3 (OG/YE) and 29S-LF7 (OG/BU). The ground for the LH front turn signal lamp is passed through circuit 31S-LG11 (BK/WH) to the front electronic module (FEM). Power is supplied from the CJB to the RH front turn signal lamp through circuits 29S-LF4 (OG/BU) and 29S-LF16 (OG/GN). The ground for the RH front turn signal lamp is passed through circuit 31S-LG18 (BK/YE) to the FEM. The FEM and rear electronic module (REM) individually control the ground circuits for the turn signal lamps. The timed on/off cycle is determined in the instrument cluster programming and is set to flash approximately 80 times per minute if both the front and rear turn signal lamps are good. If any turn signal lamp is not good, the instrument cluster will flash the remaining working turn signal lamp(s) approximately 160 times per minute.

Possible Causes
- circuit 29S-LF7 (OG/BU) open
- circuit 29S-LF16 (OG/GN) open
- circuit 31S-LG11 (BK/WH) open or short to power
- circuit 31S-LG18 (BK/YE) open or short to power
- FEM
- REM