Pinpoint Test E: The Low Beams Are Always On
Headlamps
Pinpoint Test E: The Low Beams Are Always On
Refer to Wiring Diagrams Set 85, Headlamps for schematic and connector information. Electrical Diagrams
Normal Operation
When the headlamp switch is placed in the HEADLAMPS ON position, voltage is provided to the low beam relay coil, the Instrument Cluster (IC) and the Generic Electronic Module (GEM). When the low beam relay is energized, voltage is provided through the Battery Junction Box (BJB) fuses 25 (10A) and 23 (10A) to the headlamps.
On vehicles equipped with Daytime Running Lamps (DRL), the DRL (Daytime Running Lamps) relay supplies voltage through a resistor wire to the low beams when the ignition is in RUN.
- DTC B1312 (Lamp Headlamp Input Circuit Short to Battery)- an on-demand DTC that sets when the IC (Instrument Cluster) detects a short to voltage from the headlamp switch-to-low beam relay coil circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Low beam relay
- Headlamp switch
- GEM (Generic Electronic Module)
- IC (Instrument Cluster)
PINPOINT TEST E : THE LOW BEAMS ARE ALWAYS ON
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
E1 VERIFY THE LOW BEAM RELAY OUTPUT
- Ignition OFF.
- Disconnect: Low Beam Relay.
- Ignition ON.
Do the headlamps continue to illuminate?
Yes
GO to E2.
No
GO to E5.
E2 CHECK THE LH HEADLAMP VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: BJB (Battery Junction Box) Fuse 25 (10A).
Does the LH headlamp continue to illuminate?
Yes
REPAIR circuit 15S-LE16 (GN/OG) for a short to voltage. TEST the system for normal operation.
No
GO to E3.
E3 CHECK THE RH HEADLAMP VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: BJB (Battery Junction Box) Fuse 23 (10A).
Does the RH headlamp continue to illuminate?
Yes
REPAIR circuit 15S-LE23 (GN/WH) for a short to voltage. TEST the system for normal operation.
No
If not equipped with DRL (Daytime Running Lamps), REPAIR the low beam relay output circuit for a short to voltage. TEST the system for normal operation.
If equipped with DRL (Daytime Running Lamps), GO to E4.
E4 CHECK THE DRL (Daytime Running Lamps) RELAY OUTPUT
- Connect: BJB (Battery Junction Box) Fuse 25 (10A).
- Connect: BJB (Battery Junction Box) Fuse 23 (10A).
- Disconnect: DRL (Daytime Running Lamps) Relay.
Do the headlamps continue to illuminate?
Yes
REPAIR the DRL (Daytime Running Lamps) /low beam relay output circuit for a short to voltage. TEST the system for normal operation.
No
GO to Pinpoint Test I Pinpoint Test I: The Daytime Running Lamps (DRL) Are On With The Ignition Switch Off.
E5 CHECK THE LOW BEAM RELAY
- Substitute a known good relay.
Do the headlamps continue to illuminate?
Yes
REMOVE the known good relay. GO to E6.
No
REMOVE the known good relay. INSTALL a new low beam relay. TEST the system for normal operation.
E6 CHECK THE HEADLAMP SWITCH
- Ignition OFF.
- Connect: Low Beam Relay.
- Disconnect: Headlamp Switch C205.
- Ignition ON.
Do the headlamps continue to illuminate?
Yes
GO to E7.
No
INSTALL a new headlamp switch. REFER to Headlamp Switch . TEST the system for normal operation.
E7 CHECK THE GEM (Generic Electronic Module)
- Ignition OFF.
- Disconnect: GEM (Generic Electronic Module) C201B.
- Ignition ON.
Do the headlamps continue to illuminate?
Yes
GO to E8.
No
GO to E9.
E8 CHECK THE IC (Instrument Cluster)
- Ignition OFF.
- Disconnect: IC (Instrument Cluster) C220A.
- Ignition ON.
Do the headlamps continue to illuminate?
Yes
REPAIR the headlamp switch output circuit to the low beam relay coil for a short to voltage. TEST the system for normal operation.
No
GO to E10.
E9 CHECK FOR CORRECT GEM (Generic Electronic Module) OPERATION
- Ignition OFF.
- Disconnect all the GEM (Generic Electronic Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the GEM (Generic Electronic Module) connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new GEM (Generic Electronic Module). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
E10 CHECK FOR CORRECT IC (Instrument Cluster) OPERATION
- Ignition OFF.
- Disconnect all the IC (Instrument Cluster) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the IC (Instrument Cluster) connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new IC (Instrument Cluster). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.