2001 TOYOTA PRIUS battery

I18410
Instrument Panel J/B
HTR Fuse
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±923
2001 PRIUS (RM778U)
3 Check HTR fuse.
PREPARATION:
Remove HTR fuse from instrument panel J/B.
CHECK:
Check continuity of HTR fuse.
OK:
Continuity exists.
NG Check for shot in all the harness and compo-
nents connected to the HTR fuse.
OK
Check and repair harness and connector between A/C amplifier and battery.

I18385
A/C Amplifier
A78 ECU±B
F
1W
F11
FL Block No. 1 DC/DC
Battery+B Instrument Panel J/B
R±G J25
J/C
MAINR±GF
2C5
2H1
1F13
B±G
F18
FL Block No. 2 DI±924
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
Back Up Power Source Circuit
CIRCUIT DESCRIPTION
This is the back±up power source for the A/C amplifier. Power is supplied even when the ignition switch is
off.
WIRING DIAGRAM
DI7SJ±01

I18172
+B
(+) (±)
I18410
ECU±B Fuse Instrument Panel J/B
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±925
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminal +B of A/C amplifier connector and body ground.
PREPARATION:
Remove A/C amplifier with connectors still connected.
CHECK:
Measure voltage between terminal +B of A/C amplifier connec-
tor and body ground.
OK:
Voltage : 10 ± 14 V
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI±874).
NG
2 Check ECU±B fuse.
PREPARATION:
Remove ECU±B fuse from instrument panel J/B.
CHECK:
Check continuity of ECU±B fuse.
OK:
Continuity exists.
NG Check for short in all the harness and compo-
nents connected to the ECU±B fuse (See page
IN±41).
OK
Check and repair harness and connector between A/C amplifier and battery.

I18388
A/C Amplifier
11
A7MPX+ GR
4
MPX+
BJ6
J/C
HTR Relay
J/C
Battery4
A7
MP2+ C11
Combination Meter
MPX±
11 GR±B
MPX1 MPX2
10
B8
14 13
11
B8 MPX+
MPX±
MPD2
MPD1
Instrument Panel J/B
HRLY6
2FL±O
BR R 4
1F
5 3
2
HTR
13
1J
8
1K
3
1B
3
1K
To Blower Motor
W13
IE1
R
A
J23
CJ22
R
FL Block
No. 1 DC/DC
B±G
F11 1
F13 1
1
MAINW±B
A F18
FL Block
No. 2
AWInstrument Panel J/B
1
2H
8
2K
IG1
Relay
3
25
1AM1
W±GI15
Ignition
SW
HTRAM1
3
2B
6
2D
3
2D
IG12
4
B±Y
J11
J/C
ID
IE W±BA
AJ1
J/C
3 2
E10 E10ECM
GR
GR±LC1
Gateway ECU
GR±B
J7 J/C
Engine Room J/B Body ECU DI±926
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
Heater Main Relay Circuit
CIRCUIT DESCRIPTION
The heater main relay is switched on by signals from the A/C amplifier. It supplies power to the blower motor.
WIRING DIAGRAM
DI7SK±01

BE1850 BE1844I00312125
3
125
3
4
4
I18394
Engine Room J/B
HTR
Fuse
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±927
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check heater main relay.
PREPARATION:
Remove heater main relay from engine room J/B.
CHECK:
Check continuity between each pair of terminals of heater main
relay shown below.
OK:
Tester connectionSpecified condition
1 ± 4No continuity
2 ± 4Continuity
3 ± 562.5 ± 90.9 W
PREPARATION:
Apply battery positive voltage between terminals 3 and 5.
CHECK:
Check continuity between each pair of terminal shown below.
OK:
Tester connectionSpecified condition
1 ± 2Continuity
2 ± 4No continuity
NG Replace hater main relay.
OK
2 Check HTR fuse
PREPARATION:
Remove HTR fuse from engine room J/B.
CHECK:
Check continuity of HTR fuse.
OK:
Continuity exists.
NG Check for short in all the harness and compo-
nents connected to the HTR fuse (See page
IN±41).
OK

N16333
DI±930
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check blower motor.
PREPARATION:
Remove blower motor (See page AC±33).
CHECK:
Connect positive (+) lead connected to terminal 2 of blower mo-
tor connector, negative (±) lead to terminal 1.
OK:
Blower motor operates smoothly.
NG Replace blower motor.
OK
2 Check harness and connector between battery and blower motor, blower motor
and body ground (See page IN±41).
NG Repair or replace harness or connector.
OK
3 Check harness and connector between blower motor linear controller and A/C
amplifier (See page IN±41).
NG Repair or replace harness or connector.
OK

I18387
LG±R
IE18
1
F18
FL Block No. 2
BatteryInstrument Panel J/B
I15
Ignition
SW J6
J/C
AA E1022
1F3
1A5
2D6
2K8
3
2B Engine Room J/B
IG1 Relay ACT
B±Y 35
21
4
IG1
AM1
2 W
A
J11
J/C
ID MAINFL Block No. 1
F111
F131
1DC/DC
B±GW±BA/C Amplifier
A2
A/C Magnetic
Clutch W±G AM12H1 2D3 HTRCLR MG Relay
1F4 12
5
3A85
ACT
A8 10
MGC LG±R
B±L
IE113
R
R
R
J/C
J21A
J20C
R ECM DI±932
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2001 PRIUS (RM778U)
Compressor Circuit
CIRCUIT DESCRIPTION
A/C amplifier switches the A/C magnetic clutch relay ON, thus turning the A/C compressor magnetic clutch
ON.
WIRING DIAGRAM
DI7SM±01

I18169
MGC
(+)
(±) ON
Z18060
15 2
3
12 3 5
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±933
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminal MGC of A/C amplifier and body ground.
CHECK:
(a) Start engine.
(b) Push AUTO SW.
(c) Measure voltage between terminal MGC of A/C amplifier
connector and body ground when A/C switch is On and
OFF.
OK:
A/C switchVoltage
ONBelow 0.7 V
OFF10 ± 14 V
OK Go to step 5.
NG
2 Check magnetic clutch relay.
PREPARATION:
Remove magnetic clutch relay from engine room J/B.
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 magnetic clutch relay.
OK