Daytime Running Light Operation; Headlight Operation - Toyota Camry 1999 Electrical Troubleshooting Manual

HEADLIGHT (w/ DAYTIME RUNNING LIGHT)
SYSTEM OUTLINE
The current from the FL MAIN is always flowing from the MAIN fuse to HEAD relay (Coil side) to TERMINAL H–LP of the
daytime running light relay (Main), from DOME fuse to TERMINAL +B of the daytime running light relay (Main) and from the
ALT fuse to Taillight relay (Coil side) to TERMINAL TAIL (TMMK Made) of the daytime running light relay (Main).
When the ignition SW is turned on, the current flowing through the GAUGE fuse flows to TERMINAL IG of the daytime
running light relay (Main).

1. DAYTIME RUNNING LIGHT OPERATION

When the engine is started, voltage generated at TERMINAL L of the generator is applied to TERMINAL CHG– of the
daytime running light relay (Main). If the parking brake lever is pulled up (Parking brake SW on) at this time, the relay is not
activated so the daytime running light system does not operate. If the parking brake lever is then released (Parking brake
SW off), a signal is input to TERMINAL PKB of the relay.
This activates the daytime running light relay (Main) and the HEAD relay is turned to on, so the current flows from the MAIN
fuse to the HEAD relay (Point side) to TERMINAL 1 of the DIM relay to TERMINAL 4 to H–LP LH (LWR), H–LP RH (LWR)
fuses to TERMINAL 1 of the headlights to TERMINAL 3 to TERMINAL 1 of the daytime running light resistor to TERMINAL 2
to GROUND, causing the headlights to light up (Headlights light up dimmer than normal brightness.). Once the daytime
running light system operates and the headlights light up, the headlights remain on even if the parking brake lever is pulled
up (Parking brake SW on).
If the engine stalls and the ignition SW remains on, the headlights remain light up even through current is no longer output
from TERMINAL L of the generator. If the ignition SW is then turned off, the headlights go off.
If the engine is started with the parking brake lever released (Parking brake SW off), the daytime running light system
operates and headlights light up when the engine starts.

2. HEADLIGHT OPERATION

When the light control SW is switched to HEAD position and the dimmer SW is set to LOW position, causing the daytime
running light relay (Main) and the HEAD relay to turn on, so the current flows from the MAIN fuse to HEAD relay (Point side)
to DRL NO.2 fuse to TERMINAL 3 of the DRL NO.4 relay to TERMINAL 4 to TERMINAL H–ON of the daytime running light
relay (Main) to TERMINAL H to TERMINAL 3 of the integration relay to TERMINAL 4 to TERMINAL 13 of the light control
SW to TERMINAL 16 to GROUND, activating the DRL. NO.4 relay. The current to HEAD relay (Point side) then flows to
TERMINAL 1 of the DIM relay to TERMINAL 4 to H–LP LH (LWR), H–LP RH (LWR) fuses to TERMINAL 1 of the headlights
to TERMINAL 3 to TERMINAL 1 of the DRL NO.4 relay to TERMINAL 2 to GROUND, causing the headlights to light up at
normal intensity.
When the light control SW is switched to HEAD position and the dimmer SW is set to HIGH position, the signal from the
dimmer SW is input to the daytime running light relay (Main). This activates the daytime running light relay (Main) and the
HEAD relay is turned on, so the current flows from the MAIN fuse to HEAD relay (Point side) to TERMINAL 1 of the DIM
relay to TERMINAL 3 to TERMINAL DIM of the daytime running light relay (Main), activating the DIM relay. This causes
current to flow from TERMINAL 1 of the DIM relay to TERMINAL 2 to HEAD LH (UPR), HEAD RH (UPR) fuses to TERMINAL
2 of the headlights to TERMINAL 3 to TERMINAL 1 of the DRL NO.4 relay to TERMINAL 2 to GROUND, causing the
headlights to light up at high beam and the high beam indicator light to light up.
When the dimmer SW is switched to FLASH position, the signal from the dimmer SW is input to the daytime running light
relay (Main). This activates the daytime running light relay (Main) and the HEAD relay is turned on, so the current flows from
the MAIN fuse to HEAD relay (Point side) to DRL NO.2 fuse to TERMINAL 3 of the DRL NO.4 relay to TERMINAL 4 to
TERMINAL H–ON of the daytime running light relay (Main) to TERMINAL H to TERMINAL 8 of the dimmer SW to
TERMINAL 16 to GROUND, activating the DRL NO.4 relay. At the same time, the current flows from the TERMINAL 1 of the
DIM relay to TERMINAL 3 to TERMINAL DIM of the daytime running light relay (Main), activating the DIM relay, and also
flows from the HEAD LH (UPR), HEAD RH (UPR) fuses to TERMINAL 2 of the headlights to TERMINAL 3 to TERMINAL 1 of
the DRL NO.4 relay to TERMINAL 2 to GROUND, causing the headlights to light up at high beam and the high beam
indicator light to light up.