( TL19E00K733000Y1241FAAT00 )

DTC Troubleshooting: B1241 (N and A/C ON)

DTC B1241 or DTC indicator N and A/C ON:
A Problem in the Blower Motor Circuit

1. Clear the DTC with the HDS.

1. Turn the ignition switch to LOCK (0) and then to ON (II).

1. Do the self-diagnostic function with the HDS or the heater control unit.

1. Check for DTCs.

Is DTC B1241 or N and A/C ON indicated?

YES | - | Go to Step 5 .
NO | - | Intermittent failure; check for loose wires or poor connections on the blower motor circuit.■

1. Turn the ignition switch to LOCK (0).

1. Check the No. 8 (40 A) fuse in the under-hood fuse/relay box, and the No. 16 (7.5 A) fuse in the driver's under-dash fuse/relay box.

Are the fuses OK?

YES | - | Go to Step 7 .
NO | - | Replace the fuses, and recheck.■

1. Connect the blower motor 2P connector No. 2 terminal to body ground with a jumper wire.

1. Turn the ignition switch to ON (II).

Does the blower motor run?

YES | - | Go to Step 9 .
NO | - | Go to Step 25 .

1. Turn the ignition switch to LOCK (0).

1. Disconnect the jumper wire.

1. Disconnect the power transistor 4P connector.

1. Check for continuity between the power transistor 4P connector No. 2 terminal and body ground.

Is there continuity?

YES | - | Go to Step 13 .
NO | - | Check for an open in the BLK wire between the power transistor and body ground. If the wire is OK, check for poor ground at G302.■

1. Connect the power transistor 4P connector No. 2 and No. 4 terminals with a jumper wire.

1. Turn the ignition switch to ON (II).

Does the blower motor run at high speed?

YES | - | Go to Step 15 .
NO | - | Repair open in the GRN wire between the power transistor and the blower motor.■

1. Turn the ignition switch to LOCK (0).

1. Disconnect the jumper wire.

1. Disconnect heater control unit connector B (12P).

1. Check for continuity between body ground and heater control unit connector B (12P) No. 5 and No. 6 terminals individually.

Is there continuity?

YES | - | Repair short to body ground in the wire(s) between the heater control unit and the power transistor.■
NO | - | Go to Step 19 .

1. Check for continuity between the following terminals of heater control unit connector B (12P) and the power transistor 4P connector.

   12P: | 4P:
   No. 5 | No. 1
   No. 6 | No. 3

Is there continuity?

YES | - | Go to Step 20 .
NO | - | Repair open in the wire(s) between the heater control unit and the power transistor.■

1. Turn the ignition switch to ON (II).

1. Measure the voltage between body ground and heater control unit connector B (12P) No. 5 and No. 6 terminals individually.

Is there voltage?

YES | - | Repair short to power in the wire(s).■
NO | - | Go to Step 22 .

1. Turn the ignition switch to LOCK (0).

1. Reconnect heater control unit connector B (12P).

1. Test the power transistor.

Is the power transistor OK?

YES | - | Check for loose wires or poor connections at heater control unit connector B (12P) and at the power transistor 4P connector. If the connections are good, substitute a known-good heater control unit, and recheck. If the symptom/indication goes away, replace the original heater control unit .■
NO | - | Replace the power transistor.■

1. Disconnect the jumper wire.

1. Disconnect the blower motor 2P connector.

1. Measure the voltage between the blower motor 2P connector No. 1 terminal and body ground.

Is there battery voltage?

YES | - | Replace the blower motor.■
NO | - | Go to Step 28 .

1. Turn the ignition switch to LOCK (0).

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

Is the relay OK?

YES | - | Go to Step 30 .
NO | - | Replace the blower motor relay .■

1. Check for continuity between the blower motor relay 4P socket No. 2 terminal and blower motor 2P connector No. 1 terminal.

Is there continuity?

YES | - | Go to Step 31 .
NO | - | Repair open in the wire between the blower motor relay and blower motor.■

1. Measure the voltage between the blower motor relay 4P socket No. 1 terminal and body ground.

Is there battery voltage?

YES | - | Go to Step 32 .
NO | - | Replace the under-hood fuse/relay box. ■

1. Turn the ignition switch to ON (II).

1. Measure the voltage between blower motor relay 4P socket No. 4 terminal and body ground.

Is there battery voltage?

YES | - | Check for an open in the wire between the blower motor relay 4P socket No. 4 terminal and body ground. If the wire is OK, check for poor ground at G301, LHD model, RHD model. ■
NO | - | Repair open in the wire between the No. 16 (7.5 A) fuse in the driver's under-dash fuse/relay box and blower motor relay 4P socket.■