2001 TOYOTA PRIUS Service Repair Manual

I18396
Engine Room R/B No. 3
HTR1 Fuse HTR2 Fuse
Z18060
15 2
3
123 5
DI±950
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
3 Check HTR1 and HTR2 fuses.
PREPARATION:
Remove the HTR1 and HTR2 fuses from engine room R/B NO.
3.
CHECK:
Check continuity of HTR1 and HTR2 fuses.
OK:
Continuity exists.
NG Check for short in all the harness and compo-
nents connected to the HTR1 and HTR2 fuses
(See attached wiring diagram).
OK
4 Check HTR1 and HTR2 relays.
PREPARATION:
Remove the HTR1 and HTR2 relays from engine room relay
block NO. 3.
CHECK:
Check continuity between each pair of terminals shown below
of magnetic clutch relay.
OK:
Tester connectionSpecified condition
1 ± 262.5 ± 90.9 W
3 ± 5No continuity
PREPARATION:
Apply battery positive (+) voltage between terminals 1 and 2.
CHECK:
Check continuity between terminals 3 and 5.
OK:
Continuity exists.
NG Replace HTR1 and (or) HTR2 relay.
OK

I18395
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±951
2001 PRIUS (RM778U)
5 Check harness and connector between A/C amplifier and HTR3 fuse (See page
IN±41).
NG Check and replace harness and connector.
OK
Check and replace A/C amplifier.
6 Check PTC heater (Heater Radiator).
PREPARATION:
Remove the heater radiator (See page AC±27).
CHECK:
Check continuity between terminals of PTC heater connector.
OK:
Continuity exists.
NG Replace heater radiator.
OK
Check harness and connector between PTC heater and HTR3 relay, PTC heater and body ground
(See page IN±41).

DI±952
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
Radiator Fan and Condenser Fan Circuit
CIRCUIT DESCRIPTION
The electric fan speed is controlled as described below, in accordance with the following signals:

ON/OFF signal of A/C switch

ON/OFF signal detected by the pressure switch (that cut out at medium pressure)

ON/OFF signal detected by water temperature switch
DI7SR±01

I18401
A/C Amplifier
CF Engine Room J/B
Fan No.2 Relay
A9
A91
2RF IE16
R±W R±W
1J
1A
1J
1K
1J
1K
1B
1J
1K 1K 10
11
5
3
12
5
2
3
4
7 Fan No.1 Relay
Fan No.1 Relay1
2
5 3
4
1
2
5
3
3 5
12
CDS FAN
RDIV±YJ27
J28J27 EE
E J/C L±W To Engine ECU
W±B
V±Y
From
DC/DC Fuse
From ECU±
IG Fuse 1
1 2 R1 Radiator Fan Motor
W4 Water Temp. Switch12
W±B
W±BA3 A/C Pressure Switch2 3
J1
J/CJ7
J/C
AA A
AW±BW±B
IEV±Y
A1
A/C Condenser
Fan Motor
G±W
W±G
W
L±W2
W±B W±B
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±953
2001 PRIUS (RM778U)
WIRING DIAGRAM

I18160
ON
(+) (±)CF
RF
Terminal Condition Voltage
10 ± 14 V
Below 1.0 V
Below 1.0 V
10 ± 14 V Water temp.: Below 90°C (194 °F)
Refrigerant pressure:
Below 1,520 kPa (15.5 kgf/cm
2, 220 psi) RF e Body
ground
CF e Body
ground
Water temp.: Above 90°C (194 °F)
Refrigerant pressure:
Above 1,520 kPa (15.5 kgf/cm
2, 220 psi)
A/C switch: ON
A/C switch: OFF
DI±954
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminals RF, CF of A/C amplifier and body ground.
PREPARATION:
Remove the center cluster module control with connectors still
connected.
CHECK:
(a) Start engine.
(b) Turn A/C switch ON.
(c) Measure voltage between terminal RF, CF of A/C amplifi-
er and body ground at each conditions as shown in the
chart.
OK:
OK Go to step 4.
NG
2 Check Fan No. 1, No. 2 and No. 3 relays (See page AC±65).
NG Replace faulty relay
OK