Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Rear Blower Motor Circuit
DESCRIPTION
The rear blower motor with fan sub-assembly is operated by signals from the air conditioning amplifier assembly. Rear blower motor speed signals are transmitted in accordance with changes in the duty ratio.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
Inspect the fuses for circuits related to this system before performing the following procedure.
PROCEDURE
| 1. | PERFORM ACTIVE TEST USING TECHSTREAM |
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Air Conditioner / Active Test.
(e) Check the operation by referring to the table below.
Body Electrical > Air Conditioner > Active Test| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Rear Blower Motor | Rear blower motor with fan sub-assembly | Min.: 0 Max.: 31 | - |
| Tester Display |
|---|
| Rear Blower Motor |
| OK | .gif) | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
|
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| 2. | CHECK HARNESS AND CONNECTOR (BLOWER MOTOR CONTROL - POWER SOURCE AND BODY GROUND) |
(a) Disconnect the R51 blower motor control connector.
(b) Measure the voltage and resistance according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| R51-1 (+B) - Body ground | Always | 11 to 14 V |
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| R51-6 (GND) - Body ground | Always | Below 1 Ω |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 3. | CHECK HARNESS AND CONNECTOR (BLOWER MOTOR CONTROL - AIR CONDITIONING AMPLIFIER ASSEMBLY) |
(a) Disconnect the J48 air conditioning amplifier assembly connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| R51-3 (SI) - J48-12 (BLWH) | Always | Below 1 Ω |
| R51-3 (SI) or J48-12 (BLWH) - Other terminals and body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 4. | CHECK HARNESS AND CONNECTOR (REAR BLOWER MOTOR WITH FAN SUB-ASSEMBLY - BLOWER MOTOR CONTROL AND BODY GROUND) |
(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| R50-2 (+) - R51-2 (VM) | Always | Below 1 Ω |
| R50-1 (-) - Body ground | Always | Below 1 Ω |
| R50-2 (+) or R51-2 (VM) - Other terminals and body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 5. | INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY |
| *a | Component with harness connected (Blower Motor Control) |
(a) Connect the J48 air conditioning amplifier assembly connector.
(b) Measure the waveform.
OK:
Waveform is similar to that shown in the illustration.
| Item | Content |
|---|---|
| Terminal No. | R51-3 (SI) - Body ground |
| Tool Setting | 2 V/DIV., 500 μs./DIV. |
| Vehicle Condition |
|
HINT:
The waveform varies with the blower level.
| NG | | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |
|
| 6. | INSPECT REAR BLOWER MOTOR WITH FAN SUB-ASSEMBLY |
(a) Remove the rear blower motor with fan sub-assembly connector.
Click here .gif)
(b) Inspect the rear blower motor with fan sub-assembly connector.
Click here
| OK | | REPLACE BLOWER MOTOR CONTROL |
| NG | | REPLACE REAR BLOWER MOTOR WITH FAN SUB-ASSEMBLY |
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual
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