1995 TOYOTA SUPRA door lock

INSPECTION PROCEDURE
(See page IN±30).
Check and repair harness and connector between theft deterrent and door lock ECU and horn
relay (See page IN±30).
(1) Remove instrument panel.
(See BO section)
(2) Disconnect the ECU connector.
Voltage: 10 ± 14 V
Replace telltale light RH.
Check and replace theft deterrent and door lock
ECU.
Check voltage between terminal HORN of theft deterrent and door lock
ECU connector and body ground.
Measure voltage between terminal HORN of theft
deterrent ECU connector and body ground.
± BODY ELECTRICAL SYSTEMBE±133THEFT DETERRENT AND DOOR LOCK CONTROL SYSTEM

Theft Deterrent Horn Circuit
CIRCUIT DESCRIPTION
When the theft deterrent system is activated, contact (a) and contact (b) in the ECU close alternately in cycles
of approximately 0.2 sec., causing the theft deterrent horn to blow (See the wiring diagram below).
In this condition, if any of the following operations is done, the contact (a) in the ECU opens, thus stopping the
theft deterrent horn from blowing:
(1) The front LH or RH door is unlocked with a key.
(2) The ignition switch is turned to ACC or ON position.
(3) Approximately 1 minute elapses.
BE±134± BODY ELECTRICAL SYSTEM
THEFT DETERRENT AND DOOR LOCK CONTROL SYSTEM

(See page IN±30).
Check voltage between terminal SH of theft deterrent horn connector
and body ground.
Remove the theft deterrent horn and disconnect the
connector.
Measure voltage between terminal 1 of theft deter-
rent horn connector and body ground.
Voltage: 10 ± 14 V
Check and repair harness and connector between
HORN fuse and theft deterrent horn.
Connect positive (+) lead to terminal 1 and negative
(±) lead to terminal 2 of theft deterrent horn connec-
tor.
Theft deterrent horn blows.
Replace theft deterrent horn.
Check theft deterrent horn.
Check harness and connector between theft deterrent and door lock ECU
and theft deterrent horn (See page IN±30).
Check and repair harness or connector.
Check and replace theft deterrent ECU.
INSPECTION PROCEDURE
± BODY ELECTRICAL SYSTEMBE±135THEFT DETERRENT AND DOOR LOCK CONTROL SYSTEM

Headlight Control Relay Circuit
CIRCUIT DESCRIPTION
When the theft deterrent system is activated, it causes the Tr in the ECU to switch on and off at approximately
0.2 sec. intervals. This switches the headlight control relay on and off, thus flashing the headlights (See the wir-
ing diagram below).
In this condition, if any of the following operations is done, the Tr in the ECU goes off and the headlight control
relay switches off, thus stopping the headlights flashing:
(1) The front LH or RH door is unlocked with a key.
(2) The ignition switch is turned to ACC or ON position.
(3) Approximately 1 minute elapses.
BE±136± BODY ELECTRICAL SYSTEMTHEFT DETERRENT AND DOOR LOCK CONTROL SYSTEM

INSPECTION PROCEDURE
HINT: The flow chart below is based on the premise that the headlights light up normally whenever the light con±
trol switch is operated. If headlight operation is not normal when the light control switch is operated, pro±
ceed to troubleshooting on page BE±11.
Check and replace theft deterrent and door lock
ECU.
Measure voltage between terminal HEAD of theft
deterrent ECU connector and body ground.
Voltage: 10 ± 14 V
Check and repair harness and connector between theft deterrent and door lock ECU headlight
control relay (See page IN±30).
Check voltage between terminal HEAD of theft deterrent and door lock
ECU connector and body ground.
(1) Remove instrument panel.
(See BO section)
(2) Disconnect the ECU connector.
± BODY ELECTRICAL SYSTEMBE±137THEFT DETERRENT AND DOOR LOCK CONTROL SYSTEM

Taillight Control Relay Circuit
CIRCUIT DESCRIPTION
When the theft deterrent system is activated, it causes the Tr in the ECU to switch on and off at approximately
0.2 sec. intervals. This switches the taillight control relay on and off, thus flashing the taillights (See the wiring
diagram below).
In this condition, if any of the following operations is done, the Tr in the ECU goes off and the taillight control
relay switches off, thus stopping the taillights flashing:
(1) The front LH or RH door is unlocked with a key.
(2) The ignition switch is turned to ACC or ON position.
(3) Approximately 1 minute elapses.
BE±138± BODY ELECTRICAL SYSTEMTHEFT DETERRENT AND DOOR LOCK CONTROL SYSTEM

INSPECTION PROCEDURE
(See page IN±30).
(1) Remove instrument panel.
(See BO section)
(2) Disconnect the ECU connector.
Check and replace theft deterrent ECU.
Measure voltage between terminal TAIL of theft
deterrent and door lock ECU connector and body
ground.
Voltage: 10 ± 14 V
Check and repair harness and connector between theft deterrent and door lock ECU taillight
control relay (See page IN±30).
Check voltage between terminal TAIL of theft deterrent door lock ECU
connector and body ground.
± BODY ELECTRICAL SYSTEMBE±139THEFT DETERRENT AND DOOR LOCK CONTROL SYSTEM

Ignition Switch Circuit
CIRCUIT DESCRIPTION
When the ignition switch is turned to the ACC position, battery positive voltage is applied to the terminal ACC
of the ECU. Also, if the ignition switch is turned to the ON position, battery voltage is applied to the terminals
ACC and IG of the ECU. When the battery positive voltage is applied to the terminal ACC of the ECU while the
theft deterrent system is activated, the warning stops. Furthermore, power supplied from the terminals ACC and
IG of the ECU is used as power for the door courtesy switch, and position switch, etc.
BE±140± BODY ELECTRICAL SYSTEMTHEFT DETERRENT AND DOOR LOCK CONTROL SYSTEM