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 MGC of A/C amplifier and body ground.
Check
1. Start engine.
2. Push AUTO SW.
3. Measure voltage between terminal MGC of A/C amplifier connector and body ground when A/C switch is On and OFF. If OK , see Fig 2.
  
  Fig 1: Locating A/C Amplifier MGC Terminal
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 2: A/C Amplifier MGC Terminal Specifications (A/C & Auto Switches ON)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. If OK , go to step 5.
2. NG: Go to step 2.
Check magnetic clutch relay.
PREPARATION: Remove magnetic clutch relay from engine room J/B.

Check: continuity between each pair of terminals of magnetic clutch relay. If OK , see Fig 4.

Fig 3: Identifying Magnetic Clutch Relay Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 4: Magnetic Clutch Relay Terminal Specifications
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Check: continuity between terminals 3 and 5. If OK , continuity exists.
1. NG: Replace magnetic clutch relay.
2. If OK , go to step 3.
Check A/C magnetic clutch.
PREPARATION: Disconnect magnetic clutch connector.

Check: Connect positive (+) lead connected to battery to magnetic clutch connector terminal 3 and negative (-) lead to body ground. If OK , magnetic clutch is energized.

Fig 5: Identifying Magnetic Clutch Connector Terminal 1
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: Repair A/C magnetic clutch.
2. OK: Go to step 4 .
Check harness and connector between magnetic clutch relay and A/C amplifier, A/C compressor and body ground . See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION .
1. NG: Repair or replace harness or connector.
2. If OK , proceed to next circuit inspection shown on problem symptoms table. See PROBLEM SYMPTOMS TABLE .
Check voltage between terminal ACT of A/C amplifier connector side and body ground.
Preparation
1. Disconnect A/C amplifier connector.
2. Turn ignition switch ON.
  Check: voltage between terminal ACT of A/C amplifier harness side connector.
  
  If OK , voltage : 10 - 14 V.
  
  Fig 6: Locating A/C Amplifier ACT Terminal
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: Check and replace engine ECU.
2. OK: Go to step 6 .
Check voltage between terminal ACT of A/C amplifier connector and body ground.
Preparation
1. Remove center cluster module control with connector still connected.
2. Start the engine and push AUTO switch.
  Check: the voltage between terminal ACT of A/C amplifier connector and body ground when magnetic clutch is ON and OFF by A/C switch. If OK , see Fig 8.
  
  Fig 7: Locating A/C amplifier ACT Terminal
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 8: A/C amplifier ACT Terminal Specifications (Magnetic Clutch On/Off)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: Check and replace A/C amplifier.
2. If OK , go to step 7.
Check harness and connector between magnetic clutch relay and A/C amplifier . See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION .
1. NG: Repair or replace harness or connector.
2. If OK , proceed to next circuit inspection shown on problem symptoms table. See PROBLEM SYMPTOMS TABLE .