PTC Heater Circuit: Procedure

1. Remove the HTR SUB No. 1 and HTR SUB No. 3 relays from the engine room relay block and junction block.
   Fig 1: Inspecting Relay (HTR SUB 1 And HTR SUB 3)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Specified Condition
   3 - 5	10 kΩ or higher
   3 - 5	Below 1 Ω (When battery voltage applied to terminals 1 and 2)

3. Install the HTR SUB No. 1 and HTR SUB No. 3 relays to the engine room relay block and junction block.

NG → REPLACE RELAY (HTR SUB NO. 1, HTR SUB NO. 3) 

OK: Go to next step 

1. Disconnect the connector from the A/C amplifier.
2. Remove the HTR SUB No. 1 and HTR SUB No. 3 fuses from the engine room relay block and junction block.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   E63-9 (PTC1) - HTR SUB No. 1 relay terminal 2	Always	Below 1 Ω
   E63-10 (PTC2) - HTR SUB No. 3 relay terminal 1	Always	Below 1 Ω
   E63-9 (PTC1) - Body ground	Always	10 kΩ or higher
   E63-10 (PTC2) - Body ground	Always	10 kΩ or higher
   HTR SUB No. 1 relay terminal 1 - Body ground	Always	Below 1 Ω
   HTR SUB No. 3 relay terminal 2 - Body ground	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Reconnect the connector to the A/C amplifier.
2. Remove the A/C amplifier with the connectors still connected.
   Fig 2: Identifying E63 Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   E63-9 (PTC1) - Body ground	Ignition switch ON Temperature setting: MAX. HOT Ambient temperature: 10°C (50°F) or lower Engine coolant temperature: 65°C (149°F) or lower Light control switch: OFF Blower switch: OFF	Below 1 V
   E63-9 (PTC1) - Body ground	Engine running (1250 RPM or higher) Temperature setting: MAX. HOT Ambient temperature: 10°C (50°F) or lower Engine coolant temperature: 65°C (149°F) or lower Light control switch: OFF Blower switch: ON	11 to 14 V
   E63-10 (PTC2) - Body ground	Ignition switch ON Temperature setting: MAX. HOT Ambient temperature: 10°C (50°F) or lower Engine coolant temperature: 65°C (149°F) or lower Light control switch: OFF Blower switch: OFF	Below 1 V
   E63-10 (PTC2) - Body ground	Engine running (1250 RPM or higher) Temperature setting: MAX. HOT Ambient temperature: 10°C (50°F) or lower Engine coolant temperature: 65°C (149°F) or lower Light control switch: OFF Blower switch: ON	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *a	Component with harness connected (A/C Amplifier)

NG → See step   6 

OK: Go to next step 

1. Disconnect the connector from the PTC heater.
   Fig 3: Identifying A14 & A15 Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A14-1 (B) - A15-1 (E)	Always	Below 1 Ω
   A14-3 (B) - A15-2 (E)	Always	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (PTC Heater)

NG → See step   7 

OK: Go to next step 

1. Measure the voltage according to the value(s) in the table below.
   Fig 4: Identifying A14 Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A14-1 (B) - Body ground	Ignition switch ON Temperature setting: MAX. HOT Ambient temperature: 10°C (50°F) or lower Engine coolant temperature: 65°C (149°F) or lower Light control switch: OFF Blower switch: OFF	Below 1 V
   A14-1 (B) - Body ground	Engine running (1250 RPM or higher) Temperature setting: MAX. HOT Ambient temperature: 10°C (50°F) or lower Engine coolant temperature: 65°C (149°F) or lower Light control switch: OFF Blower switch: ON	11 to 14 V
   A14-3 (B) - Body ground	Ignition switch ON Temperature setting: MAX. HOT Ambient temperature: 10°C (50°F) or lower Engine coolant temperature: 65°C (149°F) or lower Light control switch: OFF Blower switch: OFF	Below 1 V
   A14-3 (B) - Body ground	Engine running (1250 RPM or higher) Temperature setting: MAX. HOT Ambient temperature: 10°C (50°F) or lower Engine coolant temperature: 65°C (149°F) or lower Light control switch: OFF Blower switch: ON	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to PTC Heater)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → REPAIR OR REPLACE HARNESS OR CONNECTOR (PTC HEATER - BODY GROUND)