Toyota 4Runner manuals

Toyota 4Runner: 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


PROCEDURE

1.

INSPECT PTC HEATER RELAY (PTC NO. 1, PTC NO. 2, PTC NO. 3)

(a) Remove the PTC NO. 1 relay from the engine room No. 1 relay block, junction block.


(b) Remove the PTC NO. 2 and PTC NO. 3 relays from the engine room No. 2 relay block.

(c) 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 to terminals 1 and 2

10 kΩ or higher

Battery voltage is applied to terminals 1 and 2

Below 1 Ω


NG

REPLACE PTC HEATER RELAY (PTC NO. 1, PTC NO. 2, PTC NO. 3)


OK

2.

CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Remove the air conditioning amplifier assembly with its connectors still connected (See page ).



(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

F42-3 (PTC1) - Body ground

  • Engine running (1250 rpm or more)
  • Temperature setting MAX HOT
  • Outside temperature 10°C (50°F) or less
  • Engine coolant temperature 79°C (174°F) or less
  • Headlight dimmer switch off
  • Blower switch off

Below 1 V*

F42-22 (PTC2) - Body ground

  • Engine running (1250 rpm or more)
  • Temperature setting MAX HOT
  • Outside temperature 10°C (50°F) or less
  • Engine coolant temperature 76°C (169°F) or less
  • Headlight dimmer switch off
  • Blower switch off

F42-4 (PTC3) - Body ground

  • Engine running (1250 rpm or more)
  • Temperature setting MAX HOT
  • Outside temperature 10°C (50°F) or less
  • Engine coolant temperature 73°C (163°F) or less
  • Headlight dimmer switch off
  • Blower switch off

F42-3 (PTC1) - Body ground

  • Engine running (1250 rpm or more)
  • Temperature setting MAX HOT
  • Outside temperature 10°C (50°F) or less
  • Engine coolant temperature 79°C (174°F) or less
  • Headlight dimmer switch off
  • Blower switch on

11 to 14 V*

F42-22 (PTC2) - Body ground

  • Engine running (1250 rpm or more)
  • Temperature setting MAX HOT
  • Outside temperature 10°C (50°F) or less
  • Engine coolant temperature 76°C (169°F) or less
  • Headlight dimmer switch off
  • Blower switch on

F42-4 (PTC3) - Body ground

  • Engine running (1250 rpm or more)
  • Temperature setting MAX HOT
  • Outside temperature 10°C (50°F) or less
  • Engine coolant temperature 73°C (163°F) or less
  • Headlight dimmer switch off
  • Blower switch on
Text in Illustration

*a

Component with harness connected

(Air Conditioning Amplifier Assembly)

HINT:

*: After the measurement conditions are met, wait 30 seconds before performing measurements.


NG

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE


OK

3.

CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 1 RELAY BLOCK, JUNCTION BLOCK - AIR CONDITIONING AMPLIFIER)

(a) Remove the PTC NO. 1 relay from the engine room No. 1 relay block, junction block.

(b) Disconnect the F42 amplifier connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

PTC NO. 1 relay terminal 1 - F42-3 (PTC1)

Always

Below 1 Ω

PTC NO. 1 relay terminal 1 - Body ground

Always

10 kΩ or higher


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR


OK

4.

CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 2 RELAY BLOCK - AIR CONDITIONING AMPLIFIER)

(a) Remove the PTC NO. 2 and PTC NO. 3 relays from the engine room No. 2 relay block.

(b) Disconnect the F42 amplifier connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

PTC NO. 2 relay terminal 1 - F42-22 (PTC2)

Always

Below 1 Ω

PTC NO. 3 relay terminal 1 - F42-4 (PTC3)

PTC NO. 2 relay terminal 1 - Body ground

Always

10 kΩ or higher

PTC NO. 3 relay terminal 1 - Body ground


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR


OK

5.

CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 1 RELAY BLOCK, JUNCTION BLOCK - QUICK HEATER)

(a) Remove the PTC NO. 1 relay from the engine room No. 1 relay block, junction block.

(b) Disconnect the F85 heater connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

PTC NO. 1 relay terminal 3 - F85-2 (B)

Always

Below 1 Ω

PTC NO. 1 relay terminal 3 - Body ground

Always

10 kΩ or higher


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR


OK

6.

CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 2 RELAY BLOCK - QUICK HEATER)

(a) Remove the PTC NO. 2 and PTC NO. 3 relays from the engine room No. 2 relay block.

(b) Disconnect the F85 heater connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

PTC NO. 2 relay terminal 3 - F85-3 (B)

Always

Below 1 Ω

PTC NO. 3 relay terminal 3 - F85-1 (B)

PTC NO. 2 relay terminal 3 - Body ground

Always

10 kΩ or higher

PTC NO. 3 relay terminal 3 - Body ground


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR


OK

7.

CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 1 RELAY BLOCK, JUNCTION BLOCK - BATTERY AND BODY GROUND)

(a) Remove the PTC NO. 1 relay from the engine room No. 1 relay block, junction block.


(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

PTC NO. 1 relay terminal 5 - Body ground

Always

11 to 14 V

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

PTC NO. 1 relay terminal 2 - Body ground

Always

Below 1 Ω

Text in Illustration

*1

PTC NO. 1 Relay

*a

Component without relay installed

(Engine Room No. 1 Relay Block, Junction Block)


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR


OK

8.

CHECK HARNESS AND CONNECTOR (ENGINE ROOM NO. 2 RELAY BLOCK - BATTERY AND BODY GROUND)

(a) Remove the PTC NO. 2 and PTC NO. 3 relays from the engine room No. 2 relay block.


(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

PTC NO. 2 relay terminal 5 - Body ground

Always

11 to 14 V

PTC NO. 3 relay terminal 5 - Body ground

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

PTC NO. 2 relay terminal 2 - Body ground

Always

Below 1 Ω

PTC NO. 3 relay terminal 2 - Body ground

Text in Illustration

*1

PTC NO. 2 Relay

*2

PTC NO. 3 Relay

*a

Component without relay installed

(Engine Room No. 2 Relay Block)


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR


OK

9.

INSPECT QUICK HEATER ASSEMBLY

(a) Remove the quick heater assembly (See page ).



(b) 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)


NG

REPLACE QUICK HEATER ASSEMBLY


OK

10.

CHECK HARNESS AND CONNECTOR (QUICK HEATER - BODY GROUND)

(a) Disconnect the F86 heater connector.


(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

F86-1 (E) - Body ground

Always

Below 1 Ω

F86-2 (E) - Body ground

Text in Illustration

*a

Front view of wire harness connector

(to Quick Heater Assembly)


OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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