DESCRIPTION & OPERATION
Headlight and parking light system features an automatic shutoff system. With headlights and/or parking lights on, system will turn all lights off when key reminder switch is turned off (key removed from ignition). With headlights and/or parking lights on and ignition switch in LOCK or ACC position, a timer within Central Processing Unit (CPU) will begin to operate. System will turn all lights off after about 5 minutes. Timer will cancel when headlight switch of key reminder switch is turned off, or ignition switch is turned on.
If headlights have been turned off by automatic shutoff system, headlights can be turned on again by turning headlight switch off then on. With headlights and/or parking lights off, headlight switch in first or second position and driver's door switch is on (door opened), a warning buzzer in the CPU will sound twice.
Headlight system is controlled by a Central Processing Unit (CPU) located behind left kick panel. (Scheme 1) Current flows from HEAD 40-amp fuse to headlight and TNS relays, headlight switch and CPU.
Scheme 1
HEADLIGHTS & PARKING LIGHTS DO NOT TURN OFF WHEN KEY IS REMOVED FROM IGNITION
- Remove steering column cover. Disconnect key reminder switch 4-pin connector. Check continuity between terminals "A" and "B" of key reminder switch connector. (Scheme 2) With key inserted, continuity should exist. With key removed, continuity should not exist. If continuity is as specified, reconnect key reminder switch connector and go to next step. If continuity is not as specified, replace key reminder switch.
- Remove CPU from joint box. (Scheme 1) Measure voltage at terminal 3N of CPU 7-pin connector. (Scheme 3) With key inserted, battery voltage should be present. With key removed, battery voltage should not be present. If voltage is as specified, replace CPU. If voltage is not as specified, repair wiring between key reminder switch and CPU.
Scheme 2
Scheme 3
HEADLIGHTS & PARKING LIGHTS DO NOT TURN OFF AFTER 5 MINUTES WHEN IGNITION SWITCH IS TURNED TO ACC OR LOCK POSITION
- Measure voltage at terminal IG1 of ignition switch 6-pin connector. (Scheme 4) With ignition switch in ON position, battery voltage should be present. With ignition switch in any other position, battery voltage should not be present. If voltage is as specified, go to next step. If voltage is not as specified, check ignition switch. Repair or replace as necessary.
- Remove CPU from joint box. (Scheme 1) Measure voltage at terminal 3J of CPU 7-pin connector. (Scheme 3) With ignition switch in ON position, battery voltage should be present. With ignition switch in any other position, battery voltage should not be present. If voltage is as specified, replace CPU. If voltage is not as specified, repair wiring between ignition switch, METER 10-amp fuse and CPU.
Scheme 4
HEADLIGHTS & PARKING LIGHTS TURN OFF 5 MINUTES AFTER TURNED ON WHEN IGNITION IS ON
- Check 10-amp METER fuse located in fuse block, behind left kick panel. If fuse is blown, replace fuse and repair wiring as necessary. If fuse is okay, remove CPU from joint box. (Scheme 1) Measure voltage at terminal 3J of CPU 7-pin connector. (Scheme 3)
- With ignition switch in ON position, battery voltage should be present. With ignition switch in any other position, battery voltage should not be present. If voltage is as specified, replace CPU. If voltage is not as specified, repair wiring between ignition switch, 10-amp METER fuse and CPU.
BUZZER DOES NOT SOUND WHEN DRIVER'S DOOR IS OPENED WITH HEADLIGHTS & PARKING LIGHTS OFF & HEADLIGHT SWITCH IN FIRST OR SECOND POSITION.
- Remove driver's door switch. Check continuity between door switch connector terminal and door switch body. With door switch button pressed (door closed), continuity should not exist. With door switch button released (door open), continuity should exist. If continuity is as specified, reinstall driver's door switch and go to next step. If continuity is not as specified, replace driver's door switch.
- Open driver's door. Remove CPU from joint box. (Scheme 1) Check continuity between ground and terminal 3M of CPU 7-pin connector. (Scheme 3) If continuity exists, replace CPU. If continuity does not exist, repair wiring between CPU and driver's door switch.
CENTRAL PROCESSING UNIT (CPU)
Note. Remove CPU when measuring voltages at terminals 3E, 3I, 3J, 3L, 3M and 3N of CPU 14-pin connector.
With CPU connected, measure voltage at specified terminal of CPU connectors. See CPU TERMINAL VOLTAGES table. (Scheme 5) If voltage is not as specified, replace CPU.
| Terminal | Application | Condition Test | Voltage |
|---|---|---|---|
| 1I | TNS Relay | TNS Illuminated | Zero |
| 1I | TNS Relay | Other | 12 |
| 1M | Headlight Sw. | First Position (1) | Continuity |
| 2N | Headlight Sw. | Second Position (1) | Continuity |
| 3E (2) | Headlights | Illuminated (Low Beam) | 12 |
| 3I (2) | Headlight Relay | TNS Illuminated | Zero |
| 3I (2) | Headlight Relay | Other | 12 |
| 3J (2) | Ignition Switch | ON Position | 12 |
| 3L (2) | Ignition Switch | ACC Position | 12 |
| 3M (2) | Driver's Door Sw. | Open (3) | Continuity |
| 3M (2) | Driver's Door Sw. | Closed (3) | No Continuity |
| 3N (2) | Key Reminder Switch | Key Inserted | 12 |
| (1) With headlight switch on in specified position, check for continuity to body ground. (2) Remove CPU when measuring voltages. (3) With driver's door in specified position, check for continuity to body ground. | |||
| (1) | With headlight switch on in specified position, check for continuity to body ground. |
| (2) | Remove CPU when measuring voltages. |
| (3) | With driver's door in specified position, check for continuity to body ground. |
CPU TERMINAL VOLTAGES
Scheme 5
HEADLIGHT SWITCH
Disconnect headlight switch 22-pin connector. Check continuity between specified terminals of headlight switch connector with headlight switch in specified position. See HEADLIGHT SWITCH CONTINUITY table. (Scheme 6). If continuity does not exist between specified terminals, replace headlight switch.
| Position | Terminals |
|---|---|
| OFF | BA & HL |
| First (Parking Lights) | E & TNS |
| Second (Headlights) | E, TNS & HEAD |
| Low Beam (Headlights) | BA & HL |
| High Beam (Headlights) | BA & HU |
| Flash-To-Pass (Headlights) | HU & B |
HEADLIGHT SWITCH CONTINUITY
Scheme 6
HEADLIGHT RELAY
Remove headlight relay. Headlight relay is located on right inner fender panel. Check continuity between headlight relay terminals "D" and "E". (Scheme 7) If continuity exists, replace headlight relay. If continuity does not exist, apply battery voltage across headlight relay terminals "A" and "C". Check continuity between headlight relay terminals "D" and "E". If continuity exists, headlight relay is okay. If continuity does not exist, replace headlight relay.
Scheme 7
TNS RELAY
Remove TNS relay. TNS relay is located in relay block, on left inner fender panel. Check continuity between TNS relay terminals "C" and "D". (Scheme 8) If continuity exists, replace TNS relay. If continuity does not exist, apply battery voltage across TNS relay terminals "A" and "B". Check continuity between TNS relay terminals "C" and "D". If continuity exists, TNS relay is okay. If continuity does not exist, replace TNS relay.
