DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
INSPECT PTC HEATER RELAY (PTC HTR1, PTC HTR2, PTC HTR3)
CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - BATTERY)
CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - AIR CONDITIONING AMPLIFIER AND BODY GROUND)
CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - QUICK HEATER)
CHECK HARNESS AND CONNECTOR (QUICK HEATER - BODY GROUND)
INSPECT QUICK HEATER ASSEMBLY
CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY
AIR CONDITIONING SYSTEM (for Manual 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
- Inspect the fuses and relays for circuits related to this system before performing the following inspection procedure.
| 1.INSPECT PTC HEATER RELAY (PTC HTR1, PTC HTR2, PTC HTR3) |
Remove the PTC heater relays from the engine room relay block and junction block assembly.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| 3 - 5 | Battery voltage is not applied between terminals 1 and 2 | 10 kΩ or higher |
| Battery voltage is applied between terminals 1 and 2 | Below 1 Ω |
| | REPLACE PTC HEATER RELAY (PTC HTR1, PTC HTR2, PTC HTR3) |
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| 2.CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - BATTERY) |
Remove the PTC heater relays from the engine room relay block and junction block assembly.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
| Tester Connection | Condition | Specified Condition |
| PTC HTR1 relay terminal 5 - Body ground | Always | 11 to 14 V |
| PTC HTR2 relay terminal 5 - Body ground |
| PTC HTR3 relay terminal 5 - Body ground |
Text in Illustration| *a | Component without relay installed
(Engine Room Relay Block and Junction Block Assembly) |
| *1 | PTC Heater Relay (PTC HTR3) |
| *2 | PTC Heater Relay (PTC HTR2) |
| *3 | PTC Heater Relay (PTC HTR1) |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 3.CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - AIR CONDITIONING AMPLIFIER AND BODY GROUND) |
Remove the PTC heater relays from the engine room relay block and junction block assembly.
Disconnect the E81 air conditioning amplifier assembly connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| PTC HTR1 relay terminal 1 - E81-3 (PTC1) | Always | Below 1 Ω |
| PTC HTR2 relay terminal 1 - E81-22 (PTC2) |
| PTC HTR3 relay terminal 1 - E81-4 (PTC3) |
| PTC HTR1 relay terminal 1 - Body ground | Always | 10 kΩ or higher |
| PTC HTR2 relay terminal 1 - Body ground |
| PTC HTR3 relay terminal 1 - Body ground |
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| PTC HTR1 relay terminal 2 - Body ground | Always | Below 1 Ω |
| PTC HTR2 relay terminal 2 - Body ground |
| PTC HTR3 relay terminal 2 - Body ground |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 4.CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - QUICK HEATER) |
Remove the PTC heater relays from the engine room relay block and junction block assembly.
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 HTR1 relay terminal 3 - E33-2 (B) | Always | Below 1 Ω |
| PTC HTR2 relay terminal 3 - E33-1 (B) |
| PTC HTR3 relay terminal 3 - E33-3 (B) |
| PTC HTR1 relay terminal 3 - Body ground | Always | 10 kΩ or higher |
| PTC HTR2 relay terminal 3 - Body ground |
| PTC HTR3 relay terminal 3 - Body ground |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 5.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 | Below 1 Ω |
| E34-2 (E) - Body ground |
Text in Illustration| *a | Front view of wire harness connector
(to Quick Heater Assembly) |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| 6.INSPECT QUICK HEATER ASSEMBLY |
Remove the quick heater assembly ().
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
| Tester Connection | Condition | Specified Condition |
| 1 (B) - 1 (E) | Always | Below 1 kΩ |
| 2 (B) - 1 (E) |
| 2 (B) - 2 (E) |
| 3 (B) - 2 (E) |
| | REPLACE QUICK HEATER ASSEMBLY ()
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| 7.CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY |
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 idling
Set temperature MAX. HOT
Engine coolant temperature below 65°C (149°F)
Ambient temperature below 10°C (50°F)
Blower switch off → LO level | Below 1 V → 11 to 14 V* |
| E81-22 (PTC2) - Body ground |
| E81-4 (PTC3) - Body ground |
Text in Illustration| *a | Component with harness connected
(Air Conditioning Amplifier Assembly) |
- *: After the measurement conditions are met, wait 30 seconds before performing measurements.
| | REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY ()
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| OK | |
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| PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE ()
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