Toyota 2004 CELICA Electric Troubleshooting Manual page 215

AIR CONDITIONING
SYSTEM OUTLINE
1. HEATER BLOWER MOTOR OPERATION
Current is applied at all times through the HTR fuse (50A) to TERMINAL 5 of the heater relay.
When the ignition SW is turned on, current flows through the HTR fuse (10A) to TERMINAL 2 of the heater relay to the coil
side to TERMINAL 1 to TERMINAL 8 of the blower SW.
∗ Low speed operation
When the blower SW is moved to LO position, current flows to TERMINAL 8 of the blower SW to TERMINAL 1 to
GROUND, causing the heater relay to switch on. This causes the current to flow from the HTR fuse (50A) to TERMINAL
5 of the heater relay to TERMINAL 3 to TERMINAL 1 of the blower motor to TERMINAL 2 to TERMINAL 1 of the blower
resistor to TERMINAL 4 to GROUND, causing the blower motor to rotate at low speed.
∗ Medium speed operation (Operation at M1, M2)
When the blower SW is moved to M1 position, current flows to TERMINAL 8 of the blower SW to TERMINAL 1 to
GROUND, turning the heater relay to switch on. This causes the current to flow from the HTR fuse (50A) to TERMINAL
5 of the heater relay to TERMINAL 3 to TERMINAL 1 of the blower motor to TERMINAL 2 to TERMINAL 1 of the blower
resistor to TERMINAL 2 to TERMINAL 6 of the blower SW to TERMINAL 1 to GROUND. At this time, the blower
resistance of the blower resistor is less than at low speed, so the blower motor rotates at medium low speed.
When the blower SW is moved to M2 position, current flows through the motor flows from TERMINAL 1 of the blower
resistor to TERMINAL 3 to TERMINAL 5 of the blower SW to TERMINAL 1 to GROUND. At this time, resistance of the
blower resistor is less than at M1 position, so the blower motor rotates at medium high speed.
∗ High speed operation
When the blower SW is moved to HIGH position, current flows to TERMINAL 8 of the blower SW to TERMINAL 1 to
GROUND, turning the heater relay to switch on.
This causes the current to flow from the HTR fuse (50A) to TERMINAL 5 of the heater relay to TERMINAL 3 to
TERMINAL 1 of the blower motor to TERMINAL 2 to TERMINAL 4 of the blower SW to TERMINAL 1 to GROUND,
causing the blower motor to rotate at high speed.
SERVICE HINTS
B4 BLOWER RESISTOR
1-3 : Approx. 0.47 Ω
1-2 : Approx. 1.42 Ω
1-4 : Approx. 2.28 Ω
B5 BLOWER SW
8-1 : Continuity with the blower SW at LO, M1, M2 and HI position
6-1 : Continuity with the blower SW at M1 position
5-1 : Continuity with the blower SW at M2 position
4-1 : Continuity with the blower SW at HI position
: PARTS LOCATION
Code
32 (1ZZ-FE)
A2 A2
34 (2ZZ-GE)
32 (1ZZ-FE)
A3 A3
34 (2ZZ-GE)
A8 36
A9 36
: RELAY BLOCKS
Code See Page
1 26
216
See Page Code
B3
B4
B5
C12
C13
E2
Relay Blocks (Relay Block Location)
Engine Room R/B No.1 (Engine Compartment Left)
See Page
36
36
36
A 36
B 36
A 32 (1ZZ-FE)
2004 CELICA (EWD538U)
Code See Page
E3 B 32 (1ZZ-FE)
E8 E 34 (2ZZ-GE)
E12 I 34 (2ZZ-GE)
33 (1ZZ-FE)
J1 J1
35 (2ZZ-GE)