LEXUS SC400 1991 Service Repair Manual

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 3 of 6
AIR CONDITIONING CONTROL DISASSEMBLY (Cont'd):
b. Remove 2 screws and release the 6 clips to separate the Control Panel from the case.
c. Disconnect 2 connectors to separate the Control Panel from the case.
d. Remove the wire harness (See Fig. 5).
3. Remove Control Switch. a. To replace the Control Switch remove 2 screws and release 4 clips (See Fig. 6).
b. Separate Control Switch from face plate.
4. Replace the Night Illumination Bulb. Using a flat±bladed screwdriver, remove and
replace the Night Illumination Bulb.
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1992 - 1995 SC 300/400 A/C CONTROL ASSEMBLY SERVICE PARTSPage 4 of 6
INSPECTION PROCEDURE:
1. Bulb Circuit:
Bulb Inspection ± Perform the following test
on suspect Night Illumination Bulbs. Check
for continuity as shown. Replace the bulb if
there is no continuity.

Bulb Circuit Inspection ± Verify continuity
between terminals 22 and 24. If there is
no continuity, replace Control Switch.
2. Switch Circuit:
Switch Continuity Inspection ± Check that there
is continuity between the terminals while the
switch is pressed.
If there is no continuity between even one pair
of terminals, replace the Control Switch.
SWITCH
A/C
MODE/R>
MODE/L<
REAR - DEF
FRONT - DEF FRESH
RECIRC OFF
FAN - DOWN FAN - UP 13 - 17
13 - 16
13 - 15
12 - 17
12 - 16
12 - 15
12 - 14
11 - 17
11 - 16
11 - 15
INSPECTION
TERMINALS
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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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1992 - 1995 SC 300/400 A/C CONTROL ASSEMBLY SERVICE PARTSPage 6 of 6
MODEL
YEAR
Control Panel
Control Switch
Bulb
PART NUMBER INFORMATION:
PART NAME PART NUMBER MODEL APPLICATION QTY 55902-24010 `92-`94 SC 300/SC 400 1
55902-24020 `95 SC 300/SC 400 1
88601-24020 `92-`94 SC 300/SC 400 1
88601-24030 `95 SC 300/SC 400 1
84999-60360 `92-`94 SC 300/SC 400 3
84999-60340 `95 SC 300/SC 400 3
88650-24150 `92 SC 300 1
88650-24160 `92 SC 400 1
Amplifier with Case 88650-24190 `93-`94 SC 300 1
88650-24200 `93-`94 SC 400 1
88650-24231 `95 SC 300/SC 400 1
Wire Harness 88484-24010 `92-`95 SC 300/SC 400 1
Screws 90094-90416 `92-`95 SC 300/SC 400 *
* Screw Replacement not required for repair
WARRANTY INFORMATION
:
OPCODE DESCRIPTION TIME* OPN T1 T2
883851 A/C Control Assy, R&R 0.6 55900-XXXXX ** **
Combo ªAº Control Panel R&R 0.2 22902-XXXXX ** **
Combo ªCº Bulbs R&R 0.2 84999-XXXXX ** **
Combo ªDº Amplifier with Case R&R 0.2 88650-XXXXX ** ** Combo ªEº Wire Harness R&R 0.2 88484-XXXXX ** **
Combo ªGº Control Switch R&R 0.2 88601-XXXXX ** **
* Listed time for sub±operations are to be added to base operation to R\
&R the A/C control Assembly and include all necessary checks and tests.
** As applicable per the Lexus Universal Flat Rate Manual.
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TSIB
IntroductionA musty odor may be emitted from the air conditioning system of some vehicles which are
usually operated in areas with high temperature and humidity. It is most noticeable when
the air conditioner is first turned ªONº after the vehicle has bee\
n parked for several hours.
The odor could result from one or more of the following conditions:
1. Blockage of the evaporator housing drain pipe, resulting in the build up of cond\
ensation.
2. Microbial growth in the evaporator, arising from dampness in the evaporator housing
where the cooling air flow is dehumidified.
To address excessive air conditioning evaporator odor, check the evaporator housing drain
pipe for blockage. If no problems are found, the evaporator and housing\
should be cleaned
and disinfected using the general procedure given on page 2, and the model \
specific
procedure on the pages indicated in the Table of Contents at the bottom of this page.
Affected While this procedure may be used on any Lexus vehicle, this bulletin giv\
es details
Vehicles specifically for the '92±'96 ES 300, all GS 300, '93±'94 LS 400, all SC 300/400 and the\
LX 450.
Tools &
PART NUMBER DESCRIPTION OF TOOLS & MATERIALS QUANTITY SOURCE
Materials08821±00810±01 Spray Gun Kit 1 OTC 08821±00811±01 Spray Gun (replacement) (1) OTC
08821±00812±01 Spray Gun Nozzle (replacement) (1) OTC
08821±00813±01 Freshener Mixing Container (replacement) (1) OTC
08821±00801±DS Air Conditioning Freshener 1 per vehicle TMS
CAUTION:
Wear safety glasses, protective mask, and gloves while working with the
freshener.
Warranty
OPCODE DESCRIPTION TIME OPN T1 T2
Information
N/A No applicable warranty information ± ± ± ±
Table ofMODEL PAGE MODEL PAGE MODEL PAGE MODEL PAGE
Contents
ES 300 3 GS 300 5 LS 400 7
GENERAL 2
SC 300 9 SC 400 9 LX 450 11
General Procedure applies to all models and model years.
The Specific Model Sections cover only the listed ªaffected models.º
HEATING & AIR CONDITIONING
September 12, 1997
Title:
AIR CONDITIONING EVAPORATOR ODOR
Models:
'92±96 ES 300, '93±'94 LS 400,
All GS 300, SC 300/400, LX 450.
Page 1 of 11
AC001±97
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AIR CONDITIONING EVAPORATOR ODOR ± AC001±97 September 12, 1997
General1. Preparation of freshener solution:
Procedure (a) Invert freshener container and shake vigorously for 30 seconds.
(b) Mix 3.4 fl. oz. of freshener (1 container) with 30 fl. oz. to make 1 q\
t. of solution.
2. Drying the evaporator: Dry the evaporator for 10 minutes with the following settings:
A/C: Off
. . . . . . . . . . .
Air Outlet: Foot
. . . . . .
Mode: Recirc.
. . . . . . . . . .
Blower: High
. . . . . . . .
Te m p : Max Warm
. . . . . . . . . .
3. Evaporator Treatment Preparation: (a) Ensure availability of 30±45 psi compressed air to be used with spray\
gun for application of freshener.
(b) Place a tray under the evaporator housing drain hose to collect used cle\
aning solution.
(c) Place shop cloth under the evaporator housing in the vehicle to prevent \
cleaning solution from dripping onto the floor mat.
4. Vehicle Preparation: See specific model section.
5. Evaporator treatment: (a) Set HVAC mode as follows: A/C: Off
. . . . . . . . . . .
Air Outlet: Face
. . . . . .
Mode: Fresh
. . . . . . . . . .
Blower: High
. . . . . . . .
Te m p : Max Warm
. . . . . . . . . .
Windows: Open
. . . . . .
(b) Insert spray nozzle into the filter inlet and spray the entire quantity (1 qt.) of
freshener solution into the evaporator
while moving the nozzle around to
cover the complete evaporator surface.
(c) Turn the blower OFF.
6. Reinstallation of Parts.
7. Completion of Treatment. (a) Dry the evaporator for 30 minutes with the following settings:
A/C: Off
. . . . . . . . . . .
Air Outlet: Foot
. . . . . .
Mode: Recirc.
. . . . . . . . . .
Blower: High
. . . . . . . .
Te m p : Max Warm
. . . . . . . . . .
Windows: Closed
. . . . . .
(b) If the vehicle still has alcohol smell, open windows for ventilation. Do not turn on
the AC switch until the evaporator is
completely dry as this can reduce the
effectiveness of the solution.
Page 2 of 11
CAUTION
Do not get into the vehicle during
this drying operation.
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Page 3 of 11
AIR CONDITIONING EVAPORATOR ODOR ± AC001±97 September 12, 1997
ES 3001. Removal of parts.
('92±'96) (a) Pull down the carpet from the center
console as indicated by red arrow in the
illustration.
(b) Remove the plate on the side of the heater unit using steps and
,
indicated with red arrows to show
direction, in the illustration.
CAUTION:
Do not bend the cable.
NOTE:
The Plate will be reused.
(c) Remove the filter.
(d) Remove the blower controller.
2. Clean the Evaporator. Follow the general procedures given
on page 2.
NOTE:
Location for insertion of spray nozzle
is indicated by the red arrow in the
illustration.
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AIR CONDITIONING EVAPORATOR ± AC001±97 September 12, 1997
ES 3003. Reinstallation of parts.
('92±'96)
(Continued) (a) Insert the filter (up side) into the
heater unit following the numbered
steps shown in the illustration.
(b) Insert the filter (down side) into the heater unit.
(c) Reinstall the plate on the side of the heater unit using steps and
,
indicated with red arrows to show
direction, in the illustration.
CAUTION:
Confirm that the plate is secure.
(d) Restore the carpet to its original position taking care not to bend
the cable.
Page 4 of 11
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Page 5 of 11
AIR CONDITIONING EVAPORATOR ODOR ± AC001±97 September 12, 1997
GS 3001. Removal of parts.
(a) Remove the undercover.
NOTE:
Pull down the clip areas (3 places) of
the Undercover to remove.
(b) Remove the lamp.
(c) Remove the (2) wing nuts and the plate on the bottom of the cooling
unit.
CAUTION:
The plate and wing nuts will be reused.
(d) Remove the (2) filters from the cooling unit.
2. Clean the Evaporator. Follow the general procedures given on
page 2.
NOTE:
Location for insertion of spray nozzle is
indicated by the red arrow in the
illustration.
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