PTC Heater Circuit

DESCRIPTION

The GLW RLY turns on when it receives a signal from the A/C amplifier. As a result, power is supplied to the heater glow plug.

WIRING DIAGRAM

INSPECTION PROCEDURE

1. INSPECT FUSE (LH-IG, GLW PLG1, GLW PLG2)

1. Remove the LH-IG fuse from the cowl side J/B LH.

2. Remove the GLW PLG1 and GLW PLG2 fuses from the engine room R/B and J/B No. 1.

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

   Standard resistance:

   Tester Item	Condition	Specified Condition
   LH-IG fuse	Always	Below 1 Ω
   GLW PLG1 fuse	Always	Below 1 Ω
   GLW PLG2 fuse	Always	Below 1 Ω

NG	REPLACE FUSE

OK

2. INSPECT RELAY (GLW RLY1, GLW RLY2)

1. Remove the GLW RLY1 and GLW RLY2 relays from the engine room R/B and J/B No. 1.

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

   Standard resistance:

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

NG	REPLACE RELAY

OK

3. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BATTERY)

1. Disconnect the connector from the A/C amplifier.

2. Turn the engine switch on (IG).

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

   Standard voltage:

   Tester Connection (Symbols)	Condition	Specified Condition
   J58-4 (HTR2) - Body ground	Engine switch on (IG)	10 to 14 V
   J58-23 (HTR1) - Body ground	Engine switch on (IG)	10 to 14 V

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4. INSPECT AIR CONDITIONING AMPLIFIER

1. Reconnect the connector to the A/C amplifier.

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

   Standard voltage:

   Tester Connection	Condition	Specified Condition
   J58-4 (HTR2) - Body ground	Engine switch on (IG)	10 to 14 V
   J58-4 (HTR2) - Body ground	Engine switch on (IG) While the PTC operating conditions are met (engine is running at 850 rpm or more, ambient temperature is 0°C (32°F) or less, engine coolant temperature is 69°C (156°F) or less, and A/C switch setting is MAX HOT), turn the blower switch to the LO setting.	Below 1 V
   J58-23 (HTR1) - Body ground	Engine switch on (IG)	10 to 14 V
   D47-2 - Body ground	Engine switch on (IG) While the PTC operating conditions are met (engine is running at 850 rpm or more, ambient temperature is 0°C (32°F) or less, engine coolant temperature is 69°C (156°F) or less, and A/C switch setting is MAX HOT), turn the blower switch to the LO setting.	Below 1 V

NG	REPLACE AIR CONDITIONING AMPLIFIER

OK

5. INSPECT HEATER BLOWER WIRE

1. Remove the grommets and nuts of the water by-pass glow plugs.

2. Turn the engine switch on (IG).

3. Perform Active Test by referring to the table below.

   Active Test / Air Conditioner: 

   Item	Test Details / Display (Range)	Diagnostic Note
   Electric Heater 1 (Heater 1)	Electric Heater 1 / OFF, ON	-
   Electric Heater 2 (Heater 2)	Electric Heater 2 / OFF, ON	-

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

   Standard voltage:

   Tester connection	Condition	Specified condition
   1 - Body ground	Perform Active Test / HEATER 1 (Electric Heater 1): ON	10 to 14 V
   2 - Body ground	Perform Active Test / HEATER 2 (Electric Heater 2): ON	10 to 14 V

NG	REPAIR OR REPLACE HEATER BLOWER WIRE

OK

6. INSPECT WATER BY-PASS GLOW PLUG

1. Remove the water by-pass glow plug.

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

   Standard resistance:

   Below 1 Ω
   

NG	REPLACE WATER BY-PASS GLOW PLUG

OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE