Inspection Procedure

1. Remove the PTC HTR1 and PTC HTR3 fuses, and PTC HTR and PTC HTr2 H-fuses from the engine room No. 1 relay block.
2. Measure the resistance of the fuses.

   Standard resistance 

   FUSE (PTC HTR1, PTC HTr2, PTC HTR3, PTC HTR)
   
   

   Tester Connection	Condition	Specified Condition
   PTC HTR1 fuse	Always	Below 1 Ω
   PTC HTR2 H-fuse	Always	Below 1 Ω
   PTC HTR3 fuse	Always	Below 1 Ω
   PTC HTR H-fuse	Always	Below 1 Ω

NG: REPLACE FUSE 

OK: GO TO NEXT STEP 

Fig 1: Checking Air Conditioning Amplifier

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the air conditioning amplifier with its connectors still connected (see REMOVAL  ).
2. Turn the engine switch on (IG).
3. When the PTC heater operating conditions are met (engine at idling speed or faster, ambient temperature is 10°C (50°F) or less, engine coolant temperature is 65°C (149°F) or less, set temperature switch is set to MAX HOT), turn the blower switch to the LO setting.
4. Measure the voltage according to the value(s) in the table below.

   Standard voltage 

   AIR CONDITIONING AMPLIFIER
   
   

   Tester Connection	Switch Condition	Specified Condition
   L76-27 (PTC1) - Body ground	Engine switch on (IG) Blower Switch LO	11 to 14 V
   L76-26 (PTC2) - Body ground	Engine switch on (IG) Blower Switch LO	11 to 14 V
   L76-35 (PTC3) - Body ground	Engine switch on (IG) Blower Switch LO	11 to 14 V

NG: REPLACE AIR CONDITIONING AMPLIFIER (See  REMOVAL   ) 

OK: GO TO NEXT STEP 

Fig 2: Inspecting PTC Heater Relay (PTC HTR1. PTC HTr2, PTC HTR3)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the PTC heater relays from the No. 5 relay block.
2. Measure the resistance according to the value(s) in the table below.

   Standard resistance 

   PTC HEATER RELAY (PTC HTR1. PTC HTr2, PTC HTR3)
   
   

   Tester Connection	Condition	Specified Condition
   3-5	When battery voltage is not applied between terminals 1 and 2	10 kΩ or higher
   	When battery voltage is applied to terminals 1 and 2	Below 1 Ω

NG: REPLACE PTC HEATER RELAY 

OK: GO TO NEXT STEP 

Fig 3: Checking Harness And Connector (PTC Heater Relay - PTC Heater)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the PTC heater relays from the No. 5 relay block.
2. Disconnect the L40 PTC heater connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard resistance 

   PTC HEATER RELAY - PTC HEATER
   
   

   Tester Connection	Condition	Specified Condition
   PTC HTR1 terminal 3 -L40-1 (B)	Always	Below 1 Ω
   PTC HTR2 terminal 3 -L40-2 (B)	Always	Below 1 Ω
   PTC HTR3 terminal 3 -L40-3 (B)	Always	Below 1 Ω

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: GO TO NEXT STEP 

Fig 4: Checking PTC Heater

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the L40 and L41 PTC heater connectors.
2. Measure the resistance according to the value(s) in the table below.

   Standard resistance 

   PTC HEATER
   
   

   Tester Connection	Condition	Specified Condition
   L40-1 (B)-L41-1 (E)	Always	Below 1 Ω
   L40-2(B)-L41-1 (E)	Always	Below 1 Ω
   L40-1 (B)-L41-2(E)	Always	Below 1 Ω
   L40-3(B)-L41-2(E)	Always	Below 1 Ω

NG: REPLACE PTC HEATER (See  REMOVAL   ) 

OK: GO TO NEXT STEP 

Fig 5: Checking Harness And Connector (Air Conditioning Amplifier - Body Ground)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the air conditioning amplifier with its connectors still connected (see REMOVAL  ).
2. Measure the resistance according to the value(s) in the table below.

   Standard resistance 

   AIR CONDITIONING AMPLIFIER - BODY GROUND
   
   

   Tester Connection	Condition	Specified Condition
   L76-27(PTC1)-Body ground	Always	Below 1 Ω
   L76-26 (PTC2) - Body ground	Always	Below 1 Ω
   L76-35 (PTC3) - Body ground	Always	Below 1 Ω

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: REPLACE AIR CONDITIONING AMPLIFIER (See  REMOVAL   )