DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
INSPECT PTC HEATER RELAY (PTC HTR1)
INSPECT PTC HEATER RELAY (PTC HTR2)
INSPECT PTC HEATER RELAY (PTC HTR3)
CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY
CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - QUICK HEATER)
INSPECT QUICK HEATER ASSEMBLY
CHECK HARNESS AND CONNECTOR (QUICK HEATER - BODY GROUND)
CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - PTC HTR RELAY)
AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System) - PTC Heater Circuit
DESCRIPTION
PTC heater relays are closed in accordance with signals from the air conditioning amplifier assembly and power is supplied to the quick heater assembly installed on the radiator heater unit.
WIRING DIAGRAM
INSPECTION PROCEDURE
| 1.INSPECT PTC HEATER RELAY (PTC HTR1) |
Remove the PTC HTR1 relay from the engine room relay block.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| 3 - 5 | Battery voltage not applied between terminals 1 and 2 | 10 kΩ or higher |
| Battery voltage applied to terminals 1 and 2 | Below 1 Ω |
| 2.INSPECT PTC HEATER RELAY (PTC HTR2) |
Remove the PTC HTR2 relay from the engine room relay block.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| 3 - 5 | Battery voltage not applied between terminals 1 and 2 | 10 kΩ or higher |
| Battery voltage applied to terminals 1 and 2 | Below 1 Ω |
| 3.INSPECT PTC HEATER RELAY (PTC HTR3) |
Remove the PTC HTR3 relay from the engine room relay block.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| 3 - 5 | Battery voltage not applied between terminals 1 and 2 | 10 kΩ or higher |
| Battery voltage applied to terminals 1 and 2 | Below 1 Ω |
| 4.CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY |
w/ Rear Heater
Remove the air conditioning amplifier assembly with its connectors still connected ().
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Condition | Specified Condition |
| E36-27 (PTC1) - Body ground | Engine switch on (IG)
Temperature setting: MAX, HOT
MODE switch: FOOT
Engine coolant temperature: 55°C (131°F) or less
Blower switch: off | 11 to 14 V |
| E36-26 (PTC2) - Body ground |
| E36-35 (PTC3) - Body ground |
w/o Rear Heater
Remove the air conditioning amplifier assembly with its connectors still connected ().
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Condition | Specified Condition |
| E81-3 (PTC1) - Body ground | Engine switch on (IG)
Temperature setting: MAX, HOT
MODE switch: FOOT
Engine coolant temperature: 55°C (131°F) or less
Blower switch: off | 11 to 14 V |
| E81-22 (PTC2) - Body ground |
| E81-4 (PTC3) - Body ground |
| 5.CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - QUICK HEATER) |
Remove the quick heater relays from the engine room relay block.
Disconnect the E33 quick heater assembly connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| PTC HTR2 terminal 3 - E33-1 (B) | Always | Below 1 Ω |
| PTC HTR1 terminal 3 - E33-2 (B) |
| PTC HTR3 terminal 3 - E33-3 (B) |
| PTC HTR2 terminal 3 - Body ground | Always | 10 kΩ or higher |
| PTC HTR1 terminal 3 - Body ground |
| PTC HTR3 terminal 3 - Body ground |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 6.INSPECT QUICK HEATER ASSEMBLY |
Disconnect the E33 and E34 quick heater connectors.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| E33-1 (B) - E34-1 (E) | Always | Below 1 Ω |
| E33-2 (B) - E34-1 (E) |
| E33-3 (B) - E34-2 (E) |
| | REPLACE QUICK HEATER RELAY ()
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| 7.CHECK HARNESS AND CONNECTOR (QUICK HEATER - BODY GROUND) |
Disconnect the E34 quick heater assembly connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| E34-1 (E) - Body ground | Always | 10 kΩ or higher |
| E34-2 (E) - Body ground |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| 8.CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - PTC HTR RELAY) |
w/ Rear Heater
Disconnect the E36 amplifier connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| E36-27 (PTC1) - Body ground | Always | Below 1 Ω |
| E36-26 (PTC2) - Body ground |
| E36-35 (PTC3) - Body ground |
w/o Rear Heater
Disconnect the E81 amplifier connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| E81-3 (PTC1) - Body ground | Always | Below 1 Ω |
| E81-22 (PTC2) - Body ground |
| E81-4 (PTC3) - Body ground |
Result| Result | Proceed to |
| OK (for LHD) | A |
| OK (for RHD) | B |
| NG | C |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| OK | |
| |
| REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY ()
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