Toyota Scion tC 2005 - Page 232

2005 SCION tC (EWD572U)
171
Fan Motor Operation
With the ignition SW turned on, the current through the ECU–IG fuse flows to the FAN NO.1 relay (Coil side), FAN NO.2 relay
(Coil side) and FAN NO.3 relay (Coil side).
1. Low Speed Operation
Only when the A/C system is activated, the A/C condenser fan motor and the radiator fan motor rotates at low speed.
When the A/C system is activated, the current from ECU–IG fuse flows to the FAN NO.3 relay (Coil side) to TERMINAL 2 of
the diode (Fan) to TERMINAL 3 to TERMINAL (B) 2 of the engine control module causing the FAN NO.3 relay to turn on. As
a result, the current through the CDS fuse flows to TERMINAL 5 of the FAN NO.3 relay to TERMINAL 3 to TERMINAL 2 of
the A/C condenser fan motor to TERMINAL 1 to TERMINAL 3 of the FAN NO.2 relay to TERMINAL 4 to TERMINAL 2 of the
radiator fan motor to TERMINAL 1 to GROUND. As this flowing in series for the motors, the motors rotate at low speed.
2. High Speed Operation
With the pressure SW is turned on and/or the engine control module activated, the A/C condenser fan motor and the radiator
fan motor rotate at high speed.
When the pressure SW is turned on, the current through the ECU–IG fuse flows to the FAN NO.1 and NO.2 relay (Coil side)
to TERMINAL 3 of the pressure SW to TERMINAL 2 to GROUND, and the current through the ECU–IG fuse flows to the
FAN NO.3 relay (Coil side) to TERMINAL 2 of the diode (Fan) to TERMINAL 1 to TERMINAL 3 of the pressure SW to
TERMINAL 2 to GROUND. As a result, FAN NO.1, NO.2. and NO.3 relay is turned on. At the same time, the current from the
RDI fuse flows to FAN NO.1 relay (Point side) to TERMINAL 2 of the radiator fan motor to TERMINAL 1 to GROUND, and
the current from the CDS fuse flows to FAN NO.3 relay (Point side) to TERMINAL 2 of the A/C condenser fan motor to
TERMINAL 1 to TERMINAL 3 of the FAN NO.2 relay to TERMINAL 5 to GROUND.
As the current flowing in parallel for motors as above, the motors rotate at high speed.
When the engine control module activated, the current through the ECU–IG fuse flows to the FAN NO.1 and NO.2 relay (Coil
side) to TERMINAL (E) 14 of the engine control module, and the current through the ECU–IG fuse flows to the FAN NO.3
relay (Coil side) to TERMINAL 2 of the diode (Fan) to TERMINAL 1 to TERMINAL (E) 14 of the engine control module. As a
result, FAN NO.1, NO.2 and NO.3 relay is turned on. At the same time, the current from the RDI fuse flows to FAN NO.1
relay (Point side) to TERMINAL 2 of the radiator fan motor to TERMINAL 1 to GROUND, and the current from the CDS fuse
flows to FAN NO.3 relay (Point side) to TERMINAL 2 of the A/C condenser fan motor to TERMINAL 1 to TERMINAL 3 of the
FAN NO.2 relay to TERMINAL 5 to GROUND.
As the current flowing in parallel for motors as above, the motors rotate at high speed.
P5 Pressure SW
3–2 : Closed above approx. 15.5 kgf/cm
2
(220 psi, 1520 kpa)
Open below approx. 12.5 kgf/cm
2
(178 psi, 1225 kpa)
: Parts Location
Code See Page Code See Page Code See Page
A2 32 E2 32 P5 33
A7 34 E5 B 34 R1 33
D5 34 E8 E 34
:
Relay Blocks
Code See Page Relay Blocks (Relay Block Location)
2 22 Engine Room R/B (Engine Compartment Left)
:
Junction Block and Wire Harness Connector
Code See Page Junction Block and Wire Harness (Connector Location)
1B 24 Engine Room Main Wire and Instrument Panel J/B (Lower Finish Panel)
:
Connector Joining Wire Harness and Wire Harness
Code See Page Joining Wire Harness and Wire Harness (Connector Location)
EA1 38 Engine Wire and Engine Room Main Wire (Inside of the Engine Room R/B Box)
IH2 42 Engine Wire and Instrument Panel Wire (Cowl Side Panel RH)
System Outline
Service Hints