Lexus NX: Blower Motor Circuit
DESCRIPTION
The blower with fan motor sub-assembly is operated by signals from the air conditioning amplifier assembly. 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.
-
When the auxiliary battery is disconnected or the air conditioning amplifier assembly is replaced, be sure to perform servo motor initialization.
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PROCEDURE
| 1. | PERFORM ACTIVE TEST USING TECHSTREAM |
(a) Connect the Techstream to the DLC3.
(b) Turn the power 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 |
|---|---|---|---|
| Blower Motor | Blower with fan motor sub-assembly | Min.: 0 Max.: 31 | - |
| Tester Display |
|---|
| Blower Motor |
OK:
Blower with fan motor sub-assembly operates and changes speed.
| OK | .gif) | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
|
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| 2. | CHECK HARNESS AND CONNECTOR (BLOWER WITH FAN MOTOR SUB-ASSEMBLY - AIR CONDITIONING AMPLIFIER ASSEMBLY, BATTERY AND BODY GROUND) |
(a) Disconnect the I50 air conditioning amplifier assembly connector.
(b) Disconnect the I28 blower with fan motor sub-assembly connector.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
|---|---|---|
| I28-3 (+B) - Body ground | Power switch off | 11 to 14 V |
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| I28-1 (GND) - Body ground | Always | Below 1 Ω |
| I50-22 (BLW) - I28-2 (SI) | Always | Below 1 Ω |
| I50-22 (BLW) or I28-2 (SI) - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 3. | CHECK BLOWER WITH FAN MOTOR SUB-ASSEMBLY |
| (a) Disconnect the air conditioning amplifier assembly connector. |
|
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
|---|---|---|
| I50-22 (BLW) - Body ground | Power switch off | 4.5 to 5.5 V |
| NG | | REPLACE BLOWER WITH FAN MOTOR SUB-ASSEMBLY |
|
| 4. | CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY |
| *a | Component with harness connected (Air Conditioning Amplifier Assembly) |
(a) Remove the air conditioning amplifier assembly with its connectors still connected.
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(b) Turn the power switch on (IG).
(c) Turn the blower switch LO.
(d) Measure the waveform of the air conditioning amplifier assembly connector.
OK:
Waveform is similar to that shown in the illustration.
HINT:
The waveform varies with the blower speed.
| Item | Content |
|---|---|
| Tester Connection | I50-22 (BLW) - I50-14 (GND) |
| Tool setting | 1 V/DIV., 500 μs/DIV. |
| Vehicle condition | Power switch on (IG) Blower switch LO |
| OK | | REPLACE BLOWER WITH FAN MOTOR SUB-ASSEMBLY |
| NG | | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY |
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