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 converter circuit . See CONVERTER CIRCUIT .
Check voltage between terminal HTR2 of A/C amplifier and body ground.
PREPARATION: Remove the center cluster module control with connectors still connected.

Check
1. Start engine.
2. Set temperature control switch on "MAX. WARM" position.
3. Set blower switch on "HI" position.
4. Turn light control switch OFF.
5. Turn defogger switch OFF.
6. Check voltage between terminal HTR2 of A/C amplifier and body ground at each conditions, as shown in the chart. OK: See Fig 2.
  
  Fig 1: Locating A/C Amplifier Terminal HTR2
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 2: A/C Amplifier Terminal HTR2 Specifications (Max Warm)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK: Go to step 6.
2. NG: Go to step 3 .
Check HTR3 fuses.
PREPARATION: Remove the HTR3 fuse from engine room R/B No. 3.

Fig 3: Locating HTR3 Fuse
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Check: continuity of HTR1 and HTR2 fuses.

OK: Continuity exists.
1. NG: Check for short in all the harness and components connected to the HTR1 and HTR2 fuses. See Figure.
2. OK: Go to step 4.
Check HTR3 relays.
PREPARATION: Remove the HTR3 relays from engine room relay block No. 3.

Check: continuity between each pair of terminals shown below of magnetic clutch relay. OK: See Fig 5.

Fig 4: Identifying PTC Heater3 Relay Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 5: PTC Heater3 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. OK: Continuity exists.
1. NG: Replace HTR3 relay.
2. OK: Go to step 5.
Check harness and connector between A/C amplifier and HTR1 and HTR2 fuses . See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION .
1. NG: Check and replace harness and connector.
2. OK: Check and replace A/C amplifier.
Check PTC heater.
PREPARATION: Remove the heater radiator. See step 4 of INSPECTION .

Check: continuity between terminals of PTC heater connector, as shown in the chart. OK: See Fig 7.

Fig 6: Identifying PTC Heater Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 7: PTC Heater Connector Specifications
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: Replace heater radiator.
2. OK: Check harness and connector between PTC heater and HTR1, HT2 relays, PTC heater and body ground. See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION .