DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
PERFORM ACTIVE TEST BY INTELLIGENT TESTER
INSPECT FUSE
CHECK WIRE HARNESS (BLOWER MOTOR - BODY GROUND)
CHECK WIRE HARNESS (BLOWER MOTOR - BATTERY)
INSPECT BLOWER MOTOR
CHECK WIRE HARNESS (A/C AMPLIFIER - BODY GROUND)
INSPECT AIR CONDITIONING AMPLIFIER
AIR CONDITIONING SYSTEM - Blower Motor Circuit
DESCRIPTION
The blower motor is operated by signals from the A/C amplifier. The blower motor speed is controlled using various duty ratios.
Duty Ratio:
The duty ratio is the ratio of the blower motor ON time (A) to the total of the blower motor ON and OFF time (A + B).
The blower motor controller controls the blower motor speed.
WIRING DIAGRAM
INSPECTION PROCEDURE
| 1.PERFORM ACTIVE TEST BY INTELLIGENT TESTER |
Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG) and turn the intelligent tester main switch on.
Select the item below in the Active Test and then check that the relay operates.
Active Test / Air Conditioner:| Item | Test Details / Display (Range) | Diagnostic Note |
Blower Motor
(Blower Motor) | Blower motor / Min.: Level 01, Max.: Level 31 | - |
- Result:
| Result | Proceed to |
| OK | A |
| NG (blower motor does not operate) | B |
| NG (blower motor operates but does not change speed) | C |
| A | |
| |
| PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE |
|
Remove the HEATER fuse from the engine room R/B and J/B No. 1.
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
| Tester Item | Condition | Specified Condition |
| HEATER fuse | Always | Below 1 Ω |
| 3.CHECK WIRE HARNESS (BLOWER MOTOR - BODY GROUND) |
Disconnect the blower motor connector.
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
- 4GR-FSE:
| Tester Connection | Condition | Specified Condition |
| A34-1 (GND) - Body ground | Always | Below 1 Ω |
- 2AD-FHV:
| Tester Connection | Condition | Specified Condition |
| b1-1 (GND) - Body ground | Always | Below 1 Ω |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| 4.CHECK WIRE HARNESS (BLOWER MOTOR - BATTERY) |
Disconnect the blower motor connector.
Measure the voltage according to the value(s) in the table below.
- Standard voltage:
- 4GR-FSE:
| Tester Connection | Condition | Specified Condition |
| A34-3 (+B) - Body ground | Always | 10 to 14 V |
- 2AD-FHV:
| Tester Connection | Condition | Specified Condition |
| b1-3 (+B) - Body ground | Always | 10 to 14 V |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
Disconnect the A/C amplifier connector.
Connect the blower motor connector.
Measure the voltage according to the value(s) in the table below.
- Standard voltage:
- 4GR-FSE:
| Tester Connection | Condition | Specified Condition |
| A34-2 (SI) - Body ground | Engine switch on (IG) | 4.5 to 5.5 V |
- 2AD-FHV:
| Tester Connection | Condition | Specified Condition |
| b1-2 (SI) - Body ground | Engine switch on (IG) | 4.5 to 5.5 V |
| 6.CHECK WIRE HARNESS (A/C AMPLIFIER - BODY GROUND) |
Disconnect the A/C amplifier connector.
Measure the voltage according to the value(s) in the table below.
- Standard voltage:
| Tester Connection | Condition | Specified Condition |
| J58-11 (BLW) - Body ground | Engine switch on (IG) | 4.5 to 5.5 V |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| 7.INSPECT AIR CONDITIONING AMPLIFIER |
Remove the A/C amplifier with its connectors still connected.
Turn the engine switch on (IG) .
Turn the blower switch ON (Lo).
Measure the waveform between terminal J58-11 (BLW) of the A/C amplifier and body ground.
- OK:
- Waveform is as shown in the illustration.
- Waveform varies with the blower level.
| Item | Contents |
| Tool setting | 1 V/DIV., 500 μs/DIV. |
| Vehicle condition | Engine switch on (IG)
Blower switch ON (Lo) |
| | REPLACE AIR CONDITIONING AMPLIFIER |
|
|
LEXUS IS250, IS220d / GSE20 ALE20
