INSPECTION PROCEDURE 3: The heated second seat switch indicator does not illuminate at all or does not correspond to the HI/LO switch position. However, the heated seat works normally.


caution Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.

COMMENTS ON TROUBLE SYMPTOM


If the heated second seat indicator does not respond when the heated second seat switch is switched between HI and LO, the respective switch or the heated seat control unit may be defective.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE


STEP 1. Determine a trouble spot


Q. Which seat heat (second) does not work?

Left side : Go to Step 2.

Right side : Go to Step 5.

STEP 2. Check the heated seat switch (second) (LH)


(1)Remove the heated seat switch (second) (LH).
(2)Does the heated second seat switch (left) indicator illuminate when the 12V voltage is applied between Nos. 1 and 5 as well as Nos. 2 and 5 of the heated second seat (left) connector?

Q. Is the check result normal?

Go to Step 3.

Replace the heated seat switch (second) (LH).

STEP 3. Check of short to earth and open circuit in LHHI, LHLO line between the heated seat control unit connector and the heated seat switch (second) (LH) connector


Q. Is the check result normal?

Go to Step 4.

Repair the wiring harness.

STEP 4. Retest the system


Does the heated second seat (left) indicator respond when the respective heated second seat switch is switched between HI and LO?

Q. Is the check result normal?

Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction).

Replace the heated seat control unit.

STEP 5. Check the heated seat switch (second) (RH)


(1)Remove the heated seat switch (second) (RH).
(2)Does the heated second seat switch (right) indicator illuminate when the 12V voltage is applied between Nos. 1 and 5 as well as Nos. 2 and 5 of the heated second seat (right) connector?

Q. Is the check result normal?

Go to Step 6.

Replace the heated seat switch (second) (RH).

STEP 6. Check of short to earth and open circuit in RHHI, RHLO line between the heated seat control unit connector and the heated seat switch (second) (RH) connector


Q. Is the check result normal?

Go to Step 7.

Repair the wiring harness.

STEP 7. Retest the system


Does the heated second seat (right) indicator respond when the respective heated second seat switch is switched between HI and LO?

Q. Is the check result normal?

Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction).

Replace the heated seat control unit.