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 terminals IG and GND of A/C amplifier connector.
Preparation
1. Remove center cluster module control with connectors still connected.
2. Turn ignition switch ON.
  Check: Measure voltage between terminals IG and GND of A/C amplifier. If OK , voltage: 10 - 14 V.
  
  Fig 1: Locating A/C Amplifier Connector IG Terminal
  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 continuity between terminal GND of A/C amplifier and body ground.
Check: Measure resistance between terminal GND of A/C amplifier and body ground. If OK , resistance: Below 1 Ω.

Fig 2: Locating A/C Amplifier Connector GND Terminal
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: Repair or replace harness or connector.
2. If OK: Go to step 3.
Check HTR fuse.
PREPARATION: Remove HTR fuse from instrument panel J/B.

Check: continuity of HTR fuse. If OK , continuity exists.

Fig 3: Locating HTR Fuse
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: Check for shot in all the harness and components connected to the HTR fuse.
2. If OK , check and repair harness and connector between A/C amplifier and battery.