Lumbar Support Malfunction (Passenger Seat)
Diagnostic Instructions
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Seat Lumbar Support Switch B+
|
1
|
1
|
-
|
-
|
Seat Horizontal Lumbar Deflate Signal
|
1
|
2, 3
|
5
|
-
|
Seat Horizontal Lumbar Inflate Signal
|
1
|
3
|
4
|
-
|
Seat Vertical Lumbar Deflate Signal
|
1
|
2, 3
|
5
|
-
|
Seat Vertical Lumbar Inflate Signal
|
1
|
2
|
4
|
-
|
Seat Lumbar Support Pump Control
|
1
|
1
|
4
|
-
|
Seat Lumbar Support Pump Ground
|
-
|
1
|
-
|
-
|
Seat Lumbar Adjuster Valve Assembly Ground
|
-
|
1
|
-
|
-
|
1. The seat lumbar support is inoperative
2. The upper lumbar support is inoperative
3. The lower lumbar support is inoperative
4. The lumbar adjuster pump is always ON
5. The lumbar support will not inflate
|
|
|
Circuit/System Description
Battery voltage is supplied at all times to the passenger seat
lumbar support switch through a 10 A fuse located in the rear body
fuse block. When a lumbar switch is pressed to inflate the lumbar
support, battery voltage is applied through the switch contacts and
the inflate signal circuit to the seat lumbar adjuster valve
assembly. In response to this signal, the lumbar adjuster valve
assembly energizes its internal inflate solenoid and applies
battery voltage through the lumbar support pump control circuit to
the pump to inflate the appropriate support bladder until the
switch is released. When the switch is pressed to deflate the
lumbar support, battery voltage is applied through the switch
contacts and the deflate signal circuit to the seat lumbar adjuster
valve assembly. The lumbar adjuster valve assembly energizes its
internal deflate solenoid and air is released from the bladder
until the switch is released.
Reference Information
Schematic Reference
Connector End View Reference
Component Connector End Views
Description and Operation
Lumbar Support Description and Operation
Electrical Information Reference
Circuit/System Verification
1. |
Ignition ON, press and hold
the appropriate S65 seat lumbar support switch in the FORWARD
direction. The A14 seat lumbar support pump should run and the
lower lumbar bladder should start to inflate. After the lower
lumbar inflates to approximately 50%, the upper lumbar bladder
should start to inflate until both bladders are 100% inflated. The
lower lumbar will reach 100% first. |
2. |
Press the S65 seat lumbar
support switch in the REARWARD direction. The upper and lower
lumbar support bladders should deflate until the switch is
released. |
3. |
Press the S65 seat lumbar
support switch in the UP direction. The A14 seat lumbar support
pump should run and the upper lumbar support bladder should inflate
and stay inflated until the deflate switch is pressed. |
4. |
Press and hold the S65 seat
lumbar support switch in the DOWN direction. The upper lumbar
bladder should start to deflate while the lower lumbar bladder
inflates until the upper lumbar is 100% deflated and the lower
lumbar is 100% inflated. |
Circuit/System Testing
1. |
Ignition OFF, disconnect the
harness connector at the S65P passenger seat lumbar support
switch. |
2. |
Ignition ON, verify that a
test lamp illuminates between the B+ circuit terminal G and
ground. |
⇒ |
If the test lamp does not illuminate, test the B+
circuit for a short to ground or an open/high resistance. |
3. |
Ignition OFF, connect the
harness connector at the S65P passenger seat lumbar support switch
and disconnect the harness connector at the Q51P passenger seat
lumbar adjuster valve assembly. |
4. |
Test for less than 5 Ω
between the ground circuit terminal 5 and ground. |
⇒ |
If greater than the specified range, test the
ground circuit for an open/high resistance. |
5. |
Ignition ON, connect a test
lamp between each signal circuit terminal listed below and ground
one at a time. Press and release the S65 seat lumbar support switch
in the appropriate direction. The test lamp should turn ON and OFF
when changing between the commanded states. |
|
• |
Lumbar forward terminal 2
(RHD) |
|
• |
Lumbar forward terminal 4
(LHD) |
|
• |
Lumbar rearward terminal 4
(RHD) |
|
• |
Lumbar rearward terminal 2
(LHD) |
⇒ |
If the test lamp is always ON, test the signal
circuit for a short to voltage. If the circuit tests normal, test
or replace the S65 seat lumbar support switch. |
⇒ |
If the test lamp is always OFF, test the signal
circuit for a short to ground or an open/high resistance. If the
circuit tests normal, test or replace the S65 seat lumbar support
switch. |
6. |
Ignition OFF, connect the
harness connector at the Q51P passenger seat lumbar adjuster valve
assembly and disconnect the harness connector at the A14P passenger
seat lumbar support pump. |
7. |
Test for less than 5 Ω
between the ground circuit terminal 3 and ground. |
⇒ |
If greater than the specified range, test the
ground circuit for an open/high resistance. |
8. |
Connect a test lamp between
the signal circuit terminal 1 and ground. |
9. |
Ignition ON, command the A14
seat lumbar support pump ON and OFF by pressing and releasing the
S65 seat lumbar support switch in either the UP or FORWARD
direction. The test lamp should turn ON and OFF when changing
between the commanded states. |
⇒ |
If the test lamp is always ON, test the signal
circuit for a short to voltage. If the circuit tests normal, test
or replace the Q51P passenger seat lumbar adjuster valve
assembly. |
⇒ |
If the test lamp is always OFF, test the signal
circuit for a short to ground or an open/high resistance. If the
circuit tests normal, test or replace the Q51P passenger seat
lumbar adjuster valve assembly. |
10. |
If all circuits test normal,
test or replace the A14P passenger seat lumbar support pump.
|
Component Testing
Lumbar Support Switch
1. |
Ignition OFF, disconnect the
harness connector at the appropriate S65 seat lumbar support
switch. |
2. |
Test for infinite resistance
between the B+ terminal G and each signal terminal with the switch
in the open position. |
⇒ |
If not the specified value, replace the S65 seat
lumbar support switch. |
3. |
Test for less than 1 Ω
between the B+ terminal G and each signal terminal with the
appropriate switch in the closed position. |
⇒ |
If greater than the specified range, replace the
S65 seat lumbar support switch. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|