Inspection Procedure

WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.

Check voltage between terminal WP of A/C amplifier and body ground.
Preparation
1. Remove the center cluster module control with connectors still connected.
2. Start engine.
3. Operate blower motor.
  Check: Measure voltage between terminal WP of A/C amplifier and body ground when each condition as shown in the chart. If OK , see Fig 2.
  
  Fig 1: Locating A/C Amplifier Terminal WP
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 2: A/C Amplifier Terminal WP Specifications (Engine Stopped Or Running)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. If OK , proceed to next circuit inspection shown on problem symptoms table. See PROBLEM SYMPTOMS TABLE .
2. NG: Go to step 2.
Check A/C heater water pump relay.
PREPARATION: Remove the A/C heater water pump relay from engine room R/B No. 3.

Check: continuity between each pair of terminals shown in Fig 3.

Fig 3: A/C Heater Water Pump Relay Terminals Specifications
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

PREPARATION: Apply battery positive (+) voltage between terminals 1 and 2.

Fig 4: Identifying A/C Heater Water Pump Relay Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Check: continuity between terminals 3 and 5. If OK: Continuity exists.
1. NG: Replace magnetic clutch relay.
2. OK: Go to step 3.

CAUTION:

Do not apply battery voltage.
Operate without water should be done within 10 seconds
OK: Motor operation smoothly.

Fig 5: Testing Heater Water Pump Operation

Check heater water pump motor.
PREPARATION: Remove the heater water pump. See step 3) in INSPECTION .

Check: Connect the positive (+) lead from the 6 dry cell batteries (7 - 10.5 V) to terminal 1 and negative (-) lead to terminal 2, then check that the motor operation.
1. NG: Replace heater water pump.
2. OK: Go to step 4.
Check harness and connector between heater water pump motor and A/C amplifier, heater water pump motor and body ground . See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION .
1. NG: Repair or replace harness or connector.
2. OK: Check and replace A/C amplifier.