Radiator Fan High Speed Circuit Troubleshooting
Radiator Fan High Speed Circuit Troubleshooting
1.
Fuse check:

Fuse check
?1.
Check the following fuses.
Fuse
Location
No. A7 (15 A)
Under-hood fuse/relay box
No. A12-5 (30 A)
No. A12-9 (30 A)
No. A23 (7.5 A)
No. B1 (7.5 A)
Under-dash fuse/relay box

Are the fuses OK?

     
YES
     
     
     
Reinstall the fuses, then go to step 2.
     
NO
     
     
     
Replace the fuse(s), and recheck. If the fuse(s) blows again, repair the short to ground on the No. A7 (15 A), No. A12-5 (30 A), No. A12-9 (30 A), No. A23 (7.5 A), and No. B1 (7.5 A) fuses circuit.?
2.
Relay check:

Relay check
?1.
Check the following relays.
Relay
Location
Radiator fan relay
Relay circuit board
Fan control relay

Are the relays OK?

     
YES
     
     
     
Go to step 3.
     
NO
     
     
     
Replace the relay circuit board.?
3.
Determine possible failure area (under-hood fuse/relay box, fan control circuit):

Determine possible failure area (under-hood fuse/relay box, fan control circuit)
?1.
Measure the voltage between test points 1 and 2.
Test condition
OFF mode
Relay circuit board connector B (14P): disconnected
Relay circuit board connector C (10P): disconnected
Test circuit
+B MAIN FAN
Test point 1
Relay circuit board connector B (14P) No. 5 (GRN)
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
Go to step 4.
     
NO
     
     
     
Repair an open in the +B MAIN FAN wire between the relay circuit board and the under-hood fuse/relay box, No. A12-9 (30A) fuse.?
4.
Determine possible failure area (GND line, others):

Determine possible failure area (GND line, others)
?1.
Connect terminals A and B with a jumper wire.
Terminal A
Relay circuit board connector B (14P) No. 5 (GRN)
Terminal B
Relay circuit board connector B (14P) No. 13 (BLU)


Does the radiator fan run at high speed?

     
YES
     
     
     
Remove the jumper wire, then go to step 8.
     
NO
     
     
     
Remove the jumper wire, then go to step 5.
5.
Radiator fan motor operation check:

Radiator fan motor operation check
?1.
Test the radiator fan motor.

Is the motor OK?

     
YES
     
     
     
Go to step 6.
     
NO
     
     
     
6.
Open wire check (MAIN FAN MOTOR line):

Open wire check (MAIN FAN MOTOR line)
?1.
Disconnect the flowing connector.

?2.
Check for continuity between test points 1 and 2.
Test condition
OFF mode
Relay circuit board connector B (14P): disconnected
Relay circuit board connector C (10P): disconnected
 
Radiator fan motor 2P connector: disconnected
Test circuit
MAIN FAN MOTOR
Test point 1
Relay circuit board connector B (14P) No. 13 (BLU)
Test point 2
Radiator fan motor 2P connector No. 1 (BLU)


Is there continuity?

     
YES
     
     
     
Go to step 7.
     
NO
     
     
     
Repair an open in the MAIN FAN MOTOR wire between the relay circuit board and the radiator fan motor 2P connector.?
7.
Open wire check (GND line):

Open wire check (GND line)
?1.
Check for continuity between test points 1 and 2.
Test condition
OFF mode
Relay circuit board connector B (14P): disconnected
Relay circuit board connector C (10P): disconnected
 
Radiator fan motor 2P connector: disconnected
Test circuit
GND
Test point 1
Radiator fan motor 2P connector No. 2 (BLK)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Check for poor connections or loose terminals at the radiator fan motor and ground G301.?
     
NO
     
     
     
Repair an open in the GND wire between radiator fan motor 2P connector terminal No. 2 and ground G301.?
8.
Open wire check (IGP2 SUB line):

Open wire check (IGP2 SUB line)
?1.
Press the engine start/stop button to select the ON mode.

?2.
Measure the voltage between test points 1 and 2.
Test condition
ON mode
Relay circuit board connector B (14P): disconnected
Relay circuit board connector C (10P): disconnected
Test circuit
IGP2 SUB
Test point 1
Relay circuit board connector C (10P) No. 6 (PUR)
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
Go to step 9.
     
NO
     
     
     
9.
Open wire check (IG2 A/C line):

Open wire check (IG2 A/C line)
?1.
Press the engine start/stop button to select the ON mode.

?2.
Measure the voltage between test points 1 and 2.
Test condition
ON mode
Relay circuit board connector B (14P): disconnected
Relay circuit board connector C (10P): disconnected
Test circuit
IG2 A/C
Test point 1
Relay circuit board connector C (10P) No. 8 (LT GRN)
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
Go to step 10.
     
NO
     
     
     
Repair an open in the IG2 A/C wire between the relay circuit board and the under-dash fuse/relay box.?
10.
Open wire check (FAN HI SIGNAL line):

Open wire check (FAN HI SIGNAL line)
?1.
Press the engine start/stop button to select the OFF mode.

?2.
Connect the HDS to the DLC.

?3.
Press the engine start/stop button to select the ON mode.

?4.
Make sure the HDS communicates with the vehicle and the PCM. If it does not communicate, troubleshoot the DLC circuit.

?5.
Press the engine start/stop button to select the OFF mode.

?6.
Jump the SCS line with the HDS.
NOTE: This step must be done to protect the PCM from damage.


?7.
Disconnect the following connector.

?8.
Check for continuity between test points 1 and 2.
Test condition
OFF mode
Relay circuit board connector B (14P): disconnected
Relay circuit board connector C (10P): disconnected
PCM connector A (51P): disconnected
Test circuit
FAN HI SIGNAL
Test point 1
Relay circuit board connector C (10P) No. 5 (YEL)
Test point 2
PCM connector A (51P) No. 6 (YEL)


Is there continuity?

     
YES
     
     
     
Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM.?
     
NO
     
     
     
Repair an open in the FAN HI SIGNAL wire between the relay circuit board and the PCM.?