service indicator LEXUS SC400 1991 Service User Guide

PREPARATION
SST (SPECIAL SERVICE TOOLS)
SA00K±03
RECOMMENDED TOOLS
SA00L±02
EQUIPMENT
SA00M±01\
 
\

\
Dial indicator 


\
 
\


\

\

Torque wrench
±
SUSPENSION AND AXLE FRONT AXLE HUBSA±15
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DATE:JULY 19, 1996
Title1992 - 1995 SC 300/400 A/C CONTROL ASSEMBLY SERVICE PARTSPage 1 of 6
To allow repairs to the A/C Control Assembly, service parts are now available. The following
information on parts and troubleshooting will aid you in addressing comp\
laints with the LCD
display, night illumination or switch indicators.
PREVIOUSLY AVAILABLE PARTS
:
CURRENTLY AVAILABLE PARTS
:
* Face Plate is not available as a separate part.
REF: HEATING & AIR CONDITIONING
NO:AC004-96
MODEL:SC 300/400
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TROUBLE SHOOTING:
Use the matrix chart below as a guide to repairs. Verify necessary inputs to the A/C Control Assembly from
the vehicle prior to disassembly. Use the repair manual, A/C system section, to validate such as B+, IL\
L+,
ground, etc.. SUSPECT AREA
SYMPTOM Control Switch Indicator Panel Control Lamp Circuit
Night Illumination does not come on
LCD back lighting does not come on
Indicator lamps of all switches are off
Indicator lamp of all switches are on
LCD is faulty
NOTE: If symptoms still exist after the suspect areas have been tested and fou\
nd not to be
faulty, replace the amplifier.
1LCD illumination bulbs are not serviceable, Control Switch must be repla\
ced if illumination
does not occur.
AIR CONDITIONING CONTROL DISASSEMBLY
:
1. Remove Air Conditioning Control Assembly.
2. Separate Control Panel from case. a. Cut the cloth tape on both sides of the case (See Fig. 2).
1992 - 1995 SC 300/400 A/C CONTROL ASSEMBLY SERVICE PARTS Page 2 of 6
Bulb Switch


1




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1992 - 1995 SC 300/400 A/C CONTROL ASSEMBLY SERVICE PARTSPage 5 of 6
INSPECTION PROCEDURE (Cont'd):
3. Indicator Lamp Circuit: Connect two 1.5 v dry cell
batteries in series. Using the
table, check that each suspect
indicator lamp illuminates.
NOTE: Since the indicator lamps
are LEDs, do not mix the ª+º
and ª±º terminals of the test
batteries or apply power to
them for more than 3 seconds
at a time.
If a suspect LED does not illuminate
when tested, replace the Control Switch.
INDICATOR
A/C
REAR - DEF
FRONT - DEF FRESH
RECIRC TERMINAL TO
CONNECT ª+º
10
20
20
19
19 TERMINAL TO
CONNECT ª-º
18
18
8
18 8
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159
RETURN OPERATION
WHEN THE SEAT BACK IS RAISED UP FROM THE WALK±IN POSITION AND RETURNED TO THE UPRIGHT LOCK POSITION,
RECLINING LIMIT SWITCH NO. 1 OPERATES AND A SIGNAL IS INPUT TO TERMINAL RRSW OF THE POWER SEAT ECU " TERMINAL
SLD± " TERMINAL 2 OF POWER SEAT MOTOR (FOR PASSENGER'S SEAT SLIDE CONTROL) " MOTOR " TERMINAL 1 " TERMINAL
SLD+ OF ECU " TERMINAL GND " GROUND . THIS CAUSES THE SEAT TO SLIDE BACK TO A POSITION 120 MM FROM THE MOST
REAR POSITION, COMPLETING RETURN OPERATION. HOWEVER, IF THE SEAT IS POSITIONED WITHIN 120 MM OF THE MOST REAR
POSITION, RETURN OPERATION DOES NOT OCCUR, THUS MAINTAINING SUFFICIENT SPACE FOR THE REAR SEAT PASSENGER.
D10 DOOR LOCK MOTOR, DOOR UNLOCK DETECTION SW AND DOOR OPEN DETECTION SW LH
3±6 : CLOSED WITH FRONT LH DOOR OPEN
N 1 A/T INDICATOR SW [NEUTRAL START SW]
9±1 : CLOSED WITH SHIFT LEVER AT ªPº POSITION
P10(A), P11(B) POWER SEAT ECU (FOR DRIVER'S SEAT)
(A) 6±GROUND : APPROX. 12 VOLTS WITH STOP LIGHT SW ON
(B) 7±GROUND : ALWAYS APPROX. 12 VOLTS
(A) 7±GROUND : APPROX. 12 VOLTS WITH IGNITION SW ON
(A) 15±GROUND : APPROX. 12 VOLTS WITH IGNITION SW ON AND SHIFT LEVER AT ªPº RANGE
(A) 2±GROUND : APPROX. 12 VOLTS WITH DRIVER'S SEAT AT FRONT SLIDE OPERATION
(A) 9±GROUND : APPROX. 12 VOLTS WITH DRIVER'S SEAT AT REAR SLIDE OPERATION
(A) 4±GROUND : APPROX. 12 VOLTS WITH DRIVER'S SEAT AT FRONT VERTICAL UP OPERATION
(A) 11±GROUND : APPROX. 12 VOLTS WITH DRIVER'S SEAT AT FRONT VERTICAL DOWN OPERATION
(A) 13±GROUND : APPROX. 12 VOLTS WITH DRIVER'S SEAT AT REAR VERTICAL UP OPERATION
(A) 12±GROUND : APPROX. 12 VOLTS WITH DRIVER'S SEAT AT REAR VERTICAL DOWN OPERATION
(B) 18±GROUND : ALWAYS CONTINUITY
(A) 5, (A) 14±GROUND : ALWAYS APPROX. 12 VOLTS
(A) 1, (A) 8±GROUND : ALWAYS CONTINUITY
P 8 POWER SEAT CONTROL SW (FOR DRIVER'S SEAT)
4±14 : CLOSED WITH DRIVER'S SEAT AT FRONT RECLINING OPERATION
3±14 : CLOSED WITH DRIVER'S SEAT AT REAR RECLINING OPERATION
1±14 : CLOSED WITH DRIVER'S SEAT AT FRONT SLIDE OPERATION
2±14 : CLOSED WITH DRIVER'S SEAT AT REAR SLIDE OPERATION
5±14 : CLOSED WITH DRIVER'S SEAT AT FRONT VERTICAL UP OPERATION
6±14 : CLOSED WITH DRIVER'S SEAT AT FRONT VERTICAL DOWN OPERATION
9±14 : CLOSED WITH DRIVER'S SEAT AT REAR VERTICAL UP OPERATION
8±14 : CLOSED WITH DRIVER'S SEAT AT REAR VERTICAL DOWN OPERATION
P12 POWER SEAT ECU (FOR PASSENGER'S SEAT)
1±GROUND : ALWAYS APPROX. 12 VOLTS
8±GROUND : ALWAYS APPROX. 12 VOLTS
7±GROUND : APPROX. 12 VOLTS WITH PASSENGER'S SEAT AT FRONT SLIDE OPERATION
17±GROUND : APPROX. 12 VOLTS WITH PASSENGER'S SEAT AT REAR SLIDE OPERATION
S12 STOP LIGHT SW
2±1 : CLOSED WITH STOP LIGHT SW ON
SERVICE HINTS
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167
4. AUTO RETURN OPERATION
WHEN THE STEERING IS IN ªAUTO AWAYº CONDITION AND THE IGNITION KEY IS INSERTED INTO THE IGNITION KEY CYLINDER
(UNLOCK WARNING SW ON), A SIGNAL IS INPUT TO TERMINAL UWSW OF TILT AND POWER TELESCOPIC ECU.
AS A RESULT, THE TILT AND POWER TELESCOPIC ECU OPERATES AND THE CURRENT TO TERMINAL +B OF TILT AND POWER
TELESCOPIC ECU FLOWS FROM TERMINAL TEM± OF TILT AND POWER TELESCOPIC ECU "TERMINAL 4 OF COMB. SW "
TERMINAL 1 OF TELESCOPIC CONTROL MOTOR "TERMINAL 2 " TERMINAL 1 OF COMB. SW " TERMINAL TEM+ OF TILT AND
POWER TELESCOPIC ECU " TERMINAL GND2 "GROUND , AND AT THE SAME TIME, CURRENT FLOWS FROM TERMINAL TIM± OF
TILT AND POWER TELESCOPIC ECU "TERMINAL 10 OF COMB. SW "TERMINAL 1 OF TILT CONTROL MOTOR "TERMINAL 2 "
TERMINAL 1 OF COMB. SW "TERMINAL TIM+ OF TILT AND POWER TELESCOPIC ECU "TERMINAL GND2 "GROUND , CAUSING
BOTH THE TILT CONTROL MOTOR AND TELESCOPIC CONTROL MOTOR TO ROTATE. THE MOTORS CONTINUE TO ROTATE UNTIL
THE SIGNALS INPUT FROM THE TILT POSITION SENSOR TO TERMINAL TIS OF TILT AND POWER TELESCOPIC ECU AND FROM THE
TELESCOPIC POSITION SENSOR TERMINAL TES OF TILT AND POWER TELESCOPIC ECU (SIGNALS INFORMING THE ECU OF THE
CURRENT POSITION OF THE STEERING) MATCH THE POSITION MEMORIZED BY THE ECU PRIOR TO AUTO AWAY OPERATION.
IN THIS WAY, THE STEERING POSITION IS AUTOMATICALLY RETURNED TO THE ORIGINAL POSITION.
WHEN THE IGNITION SW IS TURNED FROM OFF TO ON OR THE SHIFT LEVER IS SHIFTED TO A POSITION OTHER THAN P OR N,
AUTO OPERATION IS STOPPED.
C15 TILT AND POWER TELESCOPIC UNIT [COMB. SW]
4±6 : APPROX. 160
WITH TELESCOPIC LONG OPERATION
: APPROX. 360
WITH TILT UP OPERATION
: APPROX. 790
WITH TELESCOPIC SHORT OPERATION
: APPROX. 2.0K
WITH TILT DOWN OPERATION
8±7 : CONTINUITY WITH AUTO SW OFF
8±4 : APPROX. 5K

T 7 (D) TELESCOPIC POSITION SENSOR
6±3 : APPROX. 5K

D10 DOOR LOCK MOTOR, DOOR UNLOCK DETECTION SW AND DOOR OPEN DETECTION SW LH
3±6GROUND :CLOSED WITH FRONT DOOR LH OPEN
D12 DRIVING POSITION MEMORY AND RETURN SW
2±3 : CLOSED WITH DRIVING POSITION MEMORY SW (NO. 1) ON
1±3 : CLOSED WITH DRIVING POSITION MEMORY SW (NO. 2) ON
4±3 : CLOSED WITH DRIVING POSITION MEMORY SW (SET) ON
I15 UNLOCK WARNING SW [IGNITION SW]
9±10: CLOSED WITH IGNITION KEY IN CYLINDER
N 1 A/T INDICATOR SW [NEUTRAL START SW]
9±1 : CLOSED WITH SHIFT LEVER AT P POSITION
T10, T11 TILT AND POWER TELESCOPIC ECU
(A) 4±GROUND : ALWAYS APPROX. 12 VOLTS
(A) 1±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
(B) 18±GROUND : ALWAYS APPROX. 12 VOLTS
(A) 6±GROUND : APPROX. 12 VOLTS WITH IGNITION SW ON AND SHIFT LEVER AT ªPº RANGE
(B) 10±GROUND : CONTINUITY WITH IGNITION KEY IN CYLINDER
(A) 7±GROUND : ALWAYS CONTINUITY
(B) 8±GROUND : ALWAYS CONTINUITY
(B) 2±GROUND : CONTINUITY WITH FRONT DOOR LH OPEN
(B) 3±GROUND : CONTINUITY WITH DRIVING POSITION MEMORY SW (NO. 1) ON
(B) 12±GROUND : CONTINUITY WITH DRIVING POSITION MEMORY SW (NO. 2) ON
(B) 11±GROUND : CONTINUITY WITH DRIVING POSITION MEMORY SW (SET) ON
(A) 10±GROUND : APPROX. 12 VOLTS WITH TILT UP OPERATION
(A) 3±GROUND : APPROX. 12 VOLTS WITH TILT DOWN OPERATION
(A) 2±GROUND : APPROX. 12 VOLTS WITH TELESCOPIC SHORT OPERATION
(A) 11±GROUND : APPROX. 12 VOLTS WITH TELESCOPIC LONG OPERATION
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
C1728N 127T 732
D1030P 329T10B29
D1230P1127T11A29
I1529R 732
SERVICE HINTS
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