Test E: The Electric Cooling Fan(S) Stays on All the Time

Pinpoint Test E: The Electric Cooling Fan(s) Stays On All The Time
Normal Operation
Under normal operation, in low speed, voltage is supplied to cooling fan relay 2 through circuit 1823 (YE/BK). When the relay is energized, voltage is fed to the RH cooling fan motor through circuit 1825 (LG/YE). The voltage is then fed from the RH cooling fan motor by circuit 461 (OG), to cooling fan relay 3. From cooling fan relay 3, the voltage is supplied to the circuit breaker through circuit 3850 (LG/VT). From the circuit breaker, the voltage is sent to cooling fan relay 1 through circuit 1826 (YE/RD). Cooling fan relay voltage is fed to the LH cooling fan motor by circuit 1824 (LG/VT). Ground is provided to the LH cooling fan motor, from cooling fan relay 4 (energized) through circuit 462 (VT). Ground is provided to cooling fan relay 4 through circuit 1205 (BK).

Under normal operation and in medium speed, voltage is supplied to cooling fan relay 2 through circuit 1823 (YE/BK) and to cooling fan relay 1 through circuit 1822 (LB). When the relays are energized, voltage is fed to the RH cooling fan motor through circuit 1825 (LG/YE) and to the LH cooling fan motor through circuit 1824 (LG/VT). Ground is provided to the RH cooling fan motor from circuit 1205 (BK), through the cooling fan resistor, circuit 471 (OG/LG) to cooling fan relay 5. From cooling fan relay 5, the ground is provided to cooling fan relay 3 through circuit 3828 (OG/BK) and then to the RH cooling fan motor through circuit 461 (OG). Ground is provided to the RH cooling fan motor from circuit 1205 (BK), through the cooling fan resistor, circuit 471 (OG/LG) to cooling fan relay 4. From cooling fan relay 4, the ground is provided to the LH cooling fan motor through circuit 462 (VT).

Under normal operation and in high speed, voltage is supplied to cooling fan relay 2 through circuit 1823 (YE/BK) and to cooling fan relay 1 through circuit 1822 (LB). When the relays are energized, voltage is fed to the RH cooling fan motor through circuit 1825 (LG/YE) and to the LH cooling fan motor through circuit 1824 (LG/VT). Ground for the cooling fan motors is provided through circuit 1205 (BK) to cooling fan relay 4 (LH) and 5 (RH). The LH cooling fan motor ground is received from cooling fan relay 4 (energized) through circuit 462 (VT). The RH cooling fan motor ground is received from cooling fan relay 5 (energized) through circuit 3828 (OG/BK) cooling fan relay 3 (energized) and circuit 461 (OG).

E1-E3:

E3:

NOTE: Before carrying out the following test, diagnose any PCM DTCs.

Possible Causes
^ A short to voltage on circuit 1825 (LG/YE) or 1824 (LG/VT)
^ Cooling fan relay