Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Seat Blower Control Circuit: Procedure
- CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - SEAT CLIMATE CONTROL BLOWER)
- Disconnect the connector from A/C amplifier.
- Disconnect the connector from the seat climate control blower.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition D38-16 (LOUT) - P12-3 (BCS) Always Below 1 Ω D38-16 (LOUT) - P11-3 (BBS) Always Below 1 Ω D38-8 (ROUT) - O14-3 (BCS) Always Below 1 Ω D38-8 (ROUT) - O15-3 (BBS) Always Below 1 Ω D38-16 (LOUT) - Body ground Always 10 kΩ or higher D38-8 (ROUT) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (SEAT CUSHION CLIMATE BLOWER - SEAT BACK CLIMATE BLOWER)
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition P11-2 (BFB+) - P12-2 (BFCL) Always Below 1 Ω O15-2 (BFB+) - O14-2 (BFCL) Always Below 1 Ω P11-2 (BFB+) - Body ground Always 10 kΩ or higher O15-2 (BFB+) - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- Measure the resistance according to the value(s) in the table below.
- CHECK HARNESS AND CONNECTOR (SEAT CLIMATE CONTROL BLOWER - BATTERY)
- Measure the voltage according to the value(s) in the table below.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Standard Standard
Tester Connection Condition Specified Condition P12-1 (BFC+) - Body ground Ignition switch off Below 1 Ω P12-1 (BFC+) - Body ground Ignition switch on (IG) 10 to 14 V O14-1 (BFC+) - Body ground Ignition switch off Below 1 Ω O14-1 (BFC+) - Body ground Ignition switch on (IG) 10 to 14 V Result
Result Proceed to OK A NG (w/o Smart key system) B NG (w/ Smart key system) C
B → GO TO STARTING SYSTEM
C → GO TO HOW TO PROCEED WITH TROUBLESHOOTING
A: Go to next step
- Measure the voltage according to the value(s) in the table below.
- CHECK HARNESS AND CONNECTOR (SEAT CLIMATE CONTROL BLOWER - BODY GROUND)
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition P11-1 (BFB-) - Body ground Always Below 1 Ω P12-4 (BFC-) - Body ground Always Below 1 Ω O14-4 (BFC-) - Body ground Always Below 1 Ω O15-1 (BFB-) - Body ground Always Below 1 Ω
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- Measure the resistance according to the value(s) in the table below.
- INSPECT AIR CONDITIONING AMPLIFIER
- Remove the A/C amplifier with connectors still connected.
- Turn the ignition switch on (IG).
- Measure the waveform according to the value(s).
Standard
Tester Connection Connection Specified Condition D38-8 (ROUT) - Body ground Seat heater switch: ON See Fig.86 waveform D38-16 (LOUT) - Body ground Seat heater switch: ON See Fig.86 waveform OK
Waveform appears as shown in the illustration.
HINT:
Waveform varies with the blower level.
NG → REPLACE AIR CONDITIONING AMPLIFIER
OK → REPLACE SEAT CLIMATE CONTROL BLOWER
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.