Test Q
PINPOINT TEST Q: THE FOG LAMPS ARE INOPERATIVETest Q1-Q2:
Test Q3-Q4:
Test Q5-Q7:
Test Q8:
Normal Operation
The fog lamps receive power from the fog lamp relay (when energized) through circuit 478 (TN/OG). The fog lamp switch (integral to the headlamp switch) is supplied power through circuit 1050 (LG/VT). When the fog lamp switch is engaged, power is switched to circuit 477 (LB/BK) which flows to the fog lamp relay coil. When the fog lamp relay is energized, the relay allows power from circuit 462 (VT) to flow through to circuit 478 (TN/OG). Circuit 462 (VT) is supplied power from battery junction box (BJB) fuse 44 (15A), which in turn is supplied power from the high beam relay via circuit 12 (LG/BK). When the high beam relay is energized, power to circuit 12 (LG/BK) is interrupted and the fog lamps will not illuminate. Ground for the fog lamps and relays are done through circuit 1205 (BK).
Possible Causes
- Circuit 1050 (LG/VT) open.
- Circuit 477 (LB/BK) open.
- Circuit 478 (TN/OG) open.
- Circuit 1205 (BK) open.
- Circuit 462 (VT) open.
- Circuit 12 (LG/BK) open.
- High beam relay.
- Fog lamp relay.
- Headlamp switch.