HVAC DTC Troubleshooting: 10
DTC indicator 10: A Problem in the Blower Motor Circuit
1.
Problem verification:

Problem verification
?1.
Turn the ignition switch to LOCK (0) and then back to ON (II).

?2.
Do the Self-Diagnostic Function with the HVAC control unit.

?3.
Check for DTCs.

Is DTC 10 indicated?

     
YES
     
     
     
Go to step 2.
     
NO
     
     
     
Intermittent failure. Check for loose wires or poor connections on the blower motor circuit.?
2.
Fuse check:

Fuse check
?1.
Turn the ignition switch to LOCK (0).

?2.
Check the following fuse.
Fuse
No. A14 (40 A)
Location
Under-hood fuse/relay box

Is the fuse OK?

     
YES
     
     
     
Go to step 3.
     
NO
     
     
     
Replace the fuse, and recheck. If fuse blows again, repair a short in the No. A14 (40 A) fuse circuit.?
3.
Blower motor power circuit check:

Blower motor power circuit check
?1.
Disconnect the following connector.

?2.
Turn the ignition switch to LOCK (0).

?3.
Measure the voltage between test points 1 and 2.
Test condition
IG ON (II)
Blower motor 2P connector: disconnected
Test circuit
BLW-RLY
Test point 1
Blower motor 2P connector No. 2 (WHT)
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
Go to step 4.
     
NO
     
     
     
Go to step 12.
4.
Blower motor operation check:

Blower motor operation check
?1.
Turn the ignition switch to LOCK (0).

?2.
Reconnect the blower motor 2P connector.

?3.
Connect terminals A and B with a jumper wire.
Terminal A
Blower motor 2P connector No. 1 (GRN)
Terminal B
Body ground


?4.
Turn the ignition switch ON (II).

Does the blower motor run at high speed?

     
YES
     
     
     
Go to step 5.
     
NO
     
     
     
5.
Open wire check (GND line):

Open wire check (GND line)
?1.
Turn the ignition switch to LOCK (0)..

?2.
Disconnect the jumper wire.

?3.
Disconnect the following connector.

?4.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0)
Power transistor 4P connector: disconnected
Test circuit
GND
Test point 1
Power transistor 4P connector No. 3 (BLK)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
The GND wire is OK. Go to step 6.
     
NO
     
     
     
Check for an open in the wire between the power transistor and body ground. If the wire is OK, check for poor ground at G401.?
6.
Open wire check (BLW-M line):

Open wire check (BLW-M line)
?1.
Connect terminals A and B with a jumper wire.
Terminal A
Power transistor 4P connector No. 3 (BLK)
Terminal B
Power transistor 4P connector No. 4 (GRN)


?2.
Turn the ignition switch ON (II).

Does the blower motor run at high speed?

     
YES
     
     
     
The BLW-M wire is OK. Go to step 7.
     
NO
     
     
     
Repair an open in the wire between the power transistor and the blower motor.?
7.
Shorted wire check (BLOWER V/BLW-V line):

Shorted wire check (BLOWER V/BLW-V line)
?1.
Turn the ignition switch to LOCK (0).

?2.
Disconnect the jumper wire.

?3.
Disconnect the following connector.

?4.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0)
HVAC control unit 32P connector: disconnected
Power transistor 4P connector: disconnected
Test circuit
BLOWER V/BLW-V
Test point 1
HVAC control unit 32P connector No. 24 (BLU)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short to body ground in the wire between the HVAC control unit and the power transistor.?
     
NO
     
     
     
The BLOWER V/BLW-V wire is not shorted. Go to step 8.
8.
Shorted wire check (BLOWER G/BLW-G line):

Shorted wire check (BLOWER G/BLW-G line)
?1.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0)
HVAC control unit 32P connector: disconnected
Power transistor 4P connector: disconnected
Test circuit
BLOWER G/BLW-G
Test point 1
HVAC control unit 32P connector No. 22 (YEL)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair a short to body ground in the wire between the HVAC control unit and the power transistor.?
     
NO
     
     
     
The BLOWER G/BLW-G wire is not shorted. Go to step 9.
9.
Open wire check (BLOWER G/BLW-G line):

Open wire check (BLOWER G/BLW-G line)
?1.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0)
HVAC control unit 32P connector: disconnected
Power transistor 4P connector: disconnected
Test circuit
BLOWER G/BLW-G
Test point 1
HVAC control unit 32P connector No. 22 (YEL)
Test point 2
Power transistor 4P connector No. 1 (YEL)


Is there continuity?

     
YES
     
     
     
The BLOWER G/BLW-G wire is OK. Go to step 10.
     
NO
     
     
     
Repair an open in the wire between the HVAC control unit and the power transistor.?
10.
Open wire check (BLOWER V/BLW-V line):

Open wire check (BLOWER V/BLW-V line)
?1.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0)
HVAC control unit 32P connector: disconnected
Power transistor 4P connector: disconnected
Test circuit
BLOWER V/BLW-V
Test point 1
HVAC control unit 32P connector No. 24 (BLU)
Test point 2
Power transistor 4P connector No. 2 (BLU)


Is there continuity?

     
YES
     
     
     
The BLOWER V/BLW-V wire is OK. Go to step 11.
     
NO
     
     
     
Repair an open in the wire between the HVAC control unit and the power transistor.?
11.
Power transistor check:

Power transistor check
?1.
Reconnect HVAC control unit 32P connector.

?2.
Test the power transistor.

Is the power transistor OK?

     
YES
     
     
     
     
NO
     
     
     
NOTE: If the power transistor is faulty, check the blower motor for damage. If necessary, replace the blower motor.
12.
Blower motor relay check:

Blower motor relay check
?1.
Turn the ignition switch to LOCK (0).

?2.
Remove the blower motor relay from the under-hood fuse/relay box, and test it.

Is the relay OK?

     
YES
     
     
     
Go to step 13.
     
NO
     
     
     
Replace the blower motor relay.?
13.
Open wire check (+B HTR MTR line):

Open wire check (+B HTR MTR line)
?1.
Measure the voltage between test points 1 and 2.
Test condition
IG LOCK (0)
Blower motor 2P connector: disconnected
Blower motor relay: disconnected
Test circuit
+B HTR MTR
Test point 1
Blower motor relay 4P socket No. 1
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
The +B HTR MTR wire is OK. Go to step 14.
     
NO
     
     
     
An open in +B HTR MTR wire. Replace the under-hood fuse/relay box.?
14.
Open wire check (IG2 A/C line):

Open wire check (IG2 A/C line)
?1.
Turn the ignition switch ON (II).

?2.
Measure the voltage between test points 1 and 2.
Test condition
IG ON (II)
Blower motor 2P connector: disconnected
Blower motor relay: disconnected
Test circuit
IG2 A/C
Test point 1
Blower motor relay 4P socket No. 3 (LT GRN)
Test point 2
Body ground


Is there battery voltage?

     
YES
     
     
     
The IG2 A/C wire is OK. Go to step 15.
     
NO
     
     
     
Repair an open in the wire between the relay circuit board and the blower motor relay in the under-hood fuse/relay box, or between the No. B1 (7.5 A) fuse in the under-dash fuse/relay box and the relay circuit board in the under-hood fuse/relay box. If wires are OK, replace the relay circuit board.?
15.
Open wire check (GND line):

Open wire check (GND line)
?1.
Turn the ignition switch to LOCK (0).

?2.
Check for continuity between test points 1 and 2.
Test condition
IG LOCK (0)
Blower motor 2P connector: disconnected
Blower motor relay: disconnected
Test circuit
GND
Test point 1
Blower motor relay 4P socket No. 4 (BLK)
Test point 2
Body ground


Is there continuity?

     
YES
     
     
     
Repair an open in the wire between the blower motor relay and the blower motor.?
     
NO
     
     
     
Check for an open in the wire between the blower motor relay and body ground. If the wire is OK, check for poor ground at G301.?