COMBUSTION TYPE POWER HEATER SYSTEM Power Heater Fuel Pump Circuit

DESCRIPTION

When the heater switch assembly is turned on, the heater pump assembly receives a drive voltage from the heater assembly. The heater pump assembly provides the heater assembly with fuel necessary for combustion, allowing the heater assembly to operate.

WIRING DIAGRAM

*a	Heater Pump Assembly
*b	Heater Assembly

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (HEATER ASSEMBLY - HEATER PUMP ASSEMBLY)

   
   

   1. Disconnect the A33 heater assembly connector.

   2. Disconnect the A29 heater pump assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition A33-2 (L) - A29-1 (B2) Always Below 1 Ω A33-2 (L) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

2. CHECK HARNESS AND CONNECTOR (HEATER PUMP ASSEMBLY - BODY GROUND)

   
   
   1. 

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

      Disconnect the heater pump assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition A29-2 (E2) - Body ground Always Below 1 Ω

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

3. INSPECT HEATER PUMP ASSEMBLY

   
   

   1. 

      Remove the heater pump assembly.

      Click here

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

      Standard Resistance
      Tester Connection Condition Specified Condition 1 (B2) - 2 (E2) Always 9 to 12 Ω

   3. Inspect heater pump assembly operation.

      
      

      1. Connect a positive (+) lead from the battery to terminal 1 (B2) and a negative (-) lead to terminal 2 (E2), and check the pressure of the hose by hand.

         Note

         This inspection must be done quickly (within 10 seconds) to prevent damage to the heater pump assembly.

         OK
         The pressure is applied to the hose.

      Result
      Proceed to OK NG

   
   

   NG

   REPLACE HEATER PUMP ASSEMBLY Click here

   OK

4. CHECK HEATER ASSEMBLY

   
   
   1. 

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

      Disconnect the heater pump assembly connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition A29-1 (B2) - Body ground Engine running Heater switch assembly on 11 to 14 V A29-1 (B2) - Body ground Engine running Heater switch assembly off Below 1 V

      Result
      Proceed to OK NG

   
   

   OK

   PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

   NG

   REPLACE HEATER ASSEMBLY Click here