Daytime Running Lamp: Description and Operation

System Description (For Canada)

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. If the daytime light control unit receives a ground signal from the generator (L) terminal, the daytime lights will not be illuminated. The daytime lights will illuminate once a battery positive voltage signal is sent to the daytime light control unit from the generator.

Power is supplied at all times:
- through 15 A fuse (No. [32], located in the fuse and fusible link box)
- to daytime light control unit terminal (3) and
- to lighting switch terminal (8).

Power is also supplied at all times:
- through 15 A fuse (No. [33], located in the fuse and fusible link box)
- to daytime light control unit terminal (2) and
- to lighting switch terminal (5).

With the ignition switch in the ON or START position, power is supplied:
- through 10 A fuse [No. [8], located in the fuse block (J/B)]
- to daytime light control unit terminal (12).

With the ignition switch in the START position, power is supplied: through 10 A fuse [No. [26], located in the fuse block (J/B)]
- to daytime light control unit terminal (1).

Ground is supplied to daytime light control unit terminal (9) through body grounds (E10) and (E34).

HEADLAMP OPERATION

Low Beam Operation
When the lighting switch is turned to headlamp ON (2ND) position, LOW BEAM (B), power is supplied:
- from lighting switch terminal (7)
- to RH headlamp terminal (Lo)
- to daytime light control unit terminal (4).

Ground is supplied to RH headlamp terminal (E) through body grounds (E10) and (E34).
Also, when the lighting switch is turned to headlamp ON (2ND) position, LOW BEAM (B), power is supplied:
- from lighting switch terminal (10)
- to LH headlamp terminal (Lo).

Ground is supplied:
- to LH headlamp terminal (E).
- from daytime light control unit terminal (7).
- through daytime light control unit terminal (9).
- through body grounds (E10) and (E34).

With power and ground supplied, the low beam headlamps illuminate.

High Beam Operation/Flash-To-Pass Operation
When the lighting switch is turned to headlamp ON (2ND) position, HIGH BEAM (A) or FLASH TO PASS (C) position, power is supplied:
- from lighting switch terminal (6).
- to terminal (Hi) of RH headlamp.

When the lighting switch is turned to headlamp ON (2ND) position, HIGH BEAM (A) or FLASH TO PASS (C) position, power is supplied:
- from lighting switch terminal (9).
- to daytime light control unit terminal (5)
- to combination meter terminal (46) for the high beam indicator
- through daytime light control unit terminal (6)
- to terminal (Hi) of LH headlamp.

Ground is supplied in the same manner as low beam operation.
Ground is supplied to terminal (47) of the combination meter through body grounds (M2) and (M61).
With power and ground supplied, the high beam headlamps and HI BEAM indicator illuminate.

DAYTIME LIGHT OPERATION
With the engine running, the lighting switch in the OFF or 1ST position and parking brake released, power is supplied:
- to daytime light control unit terminal (3)
- through daytime light control unit terminal (6)
- to terminal (Hi) of LH headlamp
- through terminal (E) of LH headlamp
- to daytime light control unit terminal (7)
- through daytime light control unit terminal (8)
- to terminal (Hi) of RH headlamp.

Ground is supplied to terminal (E) of RH headlamp through body grounds (E10) and (E34).
Because the high beam headlamps are now wired in series, they operate at half illumination.




Operation (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.