Daytime Running Lamp: Description and Operation

The headlamp system for Canada vehicles contains a daytime light control unit that activates the high beam headlamps at approximately half illumination whenever the engine is running. If the parking brake is applied before the engine is started the daytime lights will not be illuminated. The daytime lights will illuminate once the parking brake is released. Thereafter, the daytime lights will continue to operate when the parking brake is applied.

Power is supplied at all times
^ through 15 A fuse (No. (39) ,located in the fuse and fusible link box)
^ to daytime light control unit terminal (3) and
^ to headlamp relay terminal (3) and
^ to lighting switch terminal (8)
Power is also supplied at all times
^ through 15 A fuse (No. (40), located in the fuse and fusible link box)
^ to daytime light control unit terminal (2) and
^ to headlamp relay terminal (6) and
^ to lighting switch terminal (5)
With the ignition switch in the ON or START position, power is supplied
^ through 7.5 A fuse (No. (1),located in the fuse block)
^ to daytime light control unit terminal (12).
With the ignition switch in the START position, power is supplied
^ through 7.5 A fuse (No. (25), located in the fuse block)
^ to daytime light control unit terminal (1).
Ground is supplied to daytime light control unit terminal (9) through body grounds (E28) and (E42).

HEADLAMP OPERATION
Low beam operation
When the lighting switch is turned to the 2ND position and placed in LOW ("B") position, power is supplied
^ from lighting switch terminal (7)
^ to RH headlamp terminal (1)
^ to daytime light control unit terminal (4)
Ground is supplied to RH headlamp terminal (2) through body grounds (E28) and (E42).
Also, when the lighting switch is turned to the 2ND position and placed in LOW ("B") position, power is supplied
^ from lighting switch terminal (10)
^ to LH headlamp terminal (1).
Ground is supplied
^ to LH headlamp terminal (2)
^ from daytime light control unit terminal (7)
^ through daytime light control unit terminal (9)
^ through body grounds (E28) and (E42).
With power and ground supplied, the low beam headlamps illuminate.

High beam operation/flash-to-pass operation
When the lighting switch is turned to the 2ND position and placed in HIGH ("A") or PASS ("C") position, power is supplied
^ from lighting switch terminal (6)
^ to terminal (1) of RH headlamp (High beam)
^ to daytime light control unit terminal (8)
When the lighting switch is turned to the 2ND position and placed in HIGH ("A") or PASS ("C") position, power is supplied
^ from lighting switch terminal (9)
^ to daytime light control terminal (5)
^ to combination meter terminal (36) for the high beam indicator, and
^ to headlamp relay terminal (1)
^ through daytime light control terminal (6)
^ to terminal (1) of LH headlamp (High beam).
Ground is supplied to headlamp relay terminal (2) through body grounds (E28) and (E42).
The headlamp relay is energized and power is supplied
^ from headlamp relay terminals (5) and (7)
^ to terminal (1) of each headlamp (Low beam).
Ground is supplied
^ to terminal (2) of each RH headlamp (High and Low beams)
^ through body grounds (E28) and (E42)
^ to terminal (2) of each LH headlamp (High and Low beams)
^ from daytime light control unit terminal (7)
^ through daytime light control unit terminal (9)
^ through body grounds (E28) and (E42).
Ground is also supplied to terminal (22) of the combination meter through body grounds (M55) and (M57). With power and ground supplied, all the headlamps (High and Low beams) and the high beam indicator illuminate.

DAYTIME LIGHT OPERATION
With the engine running and the lighting switch in the OFF position, power is supplied
^ to daytime light control unit terminal (3)
^ through daytime light control unit terminal (6)
^ to terminal (1) of LH headlamp (High beam)
^ through terminal (2) of LH headlamp
^ to daytime light control unit terminal (7)
^ through daytime light control unit terminal (8)
^ to terminal (1) of RH headlamp (High beam).
Ground is supplied to terminal (2) of RH headlamp through body grounds (E28) and (E42).
Because the high beam headlamps are now wired in series, they operate at half illumination.

Operation (Daytime Light System For Canada):

Operation (Daytime light system for Canada)
After starting the engine with the lighting switch in the "OFF" or "1ST" position, the headlamp high beam automatically turns on. Lighting switch operations other than the above are the same as conventional light systems.