Pinpoint Test R: Both Front Fog Lamps Are Inoperative
Fog Lamps
Pinpoint Tests
Pinpoint Test R: Both Front Fog Lamps Are Inoperative
Refer to Wiring Diagram Set 86, Fog Lamps for schematic and connector information. Diagrams By Number
Normal Operation
The Central Junction Box (CJB) fuse 147 (15A) provides voltage at all times to the front fog lamp relay. When the ignition is in RUN, the CJB fuse 141 (7.5A) provides voltage to the front fog lamp switch (part of the headlamp switch). When the headlamp switch is placed in the PARKING LAMPS or HEADLAMPS ON position and the knob is pulled to the first detent, the headlamp switch provides voltage to the front fog lamp relay coil. Voltage is provided to the front fog lamps when the front fog lamp energizes.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Front fog lamp relay
- Headlamp switch
PINPOINT TEST R: BOTH FRONT FOG LAMPS ARE INOPERATIVE
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
-------------------------------------------------
R1 CHECK THE FRONT FOG LAMP RELAY
- Ignition OFF.
- Disconnect: Front Fog Lamp Relay.
- Substitute a known good relay and recheck the front fog lamp operation.
- Do the front fog lamps illuminate?
Yes
REMOVE the known good relay. INSTALL a new front fog lamp relay. TEST the system for normal operation.
No
REMOVE the known good relay. GO to R2.
-------------------------------------------------
R2 CHECK FOR VOLTAGE TO THE FRONT FOG LAMP RELAY
- Ignition OFF.
- Measure the voltage between the front fog lamp relay pin 3, circuit 29-LD1 (OG/YE), CJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to R3.
No
VERIFY the CJB fuse 147 (15A) is OK. If OK, REPAIR circuit 29-LD1 (OG/YE) for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
-------------------------------------------------
R3 CHECK THE FRONT FOG LAMP RELAY GROUND CIRCUIT FOR AN OPEN
- Measure the voltage between the front fog lamp relay pin 3, circuit 29-LD1 (OG/YE), CJB face side and the front fog lamp relay pin 2, circuit 91-LD8 (BK/OG), CJB face side.
- Is the voltage greater than 10 volts?
Yes
GO to R4.
No
REPAIR circuit 91-LD8 (BK/OG) for an open. TEST the system for normal operation.
-------------------------------------------------
R4 BYPASS THE FRONT FOG LAMP RELAY
- Connect a fused jumper wire between the front fog lamp relay pin 3, circuit 29-LD1 (OG/YE), CJB face side and the front fog lamp relay pin 5, circuit 15S-LD1 (GN/YE), CJB face side.
- Do the front fog lamps illuminate?
Yes
REMOVE The jumper wire. GO to R5.
No
REMOVE The jumper wire. REPAIR circuit 15S-LD1 (GN/YE) for an open. TEST the system for normal operation.
-------------------------------------------------
R5 CHECK FOR VOLTAGE TO THE HEADLAMP SWITCH
- Connect: Front Fog Lamp Relay.
- Disconnect: Headlamp Switch C205.
- Ignition ON.
- Measure the voltage between the headlamp switch C205-7, circuit 15-LD16 (GN/RD), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to R6.
No
VERIFY the CJB fuse 141 (7.5A) is OK. If OK, REPAIR circuit 15-LD16 (GN/RD) for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
-------------------------------------------------
R6 BYPASS THE HEADLAMP SWITCH
- Connect a fuse jumper wire between the headlamp switch C205-7, circuit 15-LD16 (GN/RD), harness side and the headlamp switch C205-3, circuit 15-LD1 (GN/YE), harness side.
- Do the front fog lamps illuminate?
Yes
REMOVE the jumper wire. INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. TEST the system for normal operation.
No
REMOVE the jumper wire. REPAIR circuit 15-LD1 (GN/YE) for an open. TEST the system for normal operation.
-------------------------------------------------