Blower Request Circuit Troubleshooting
Blower Request Circuit Troubleshooting
NOTE:
Do not use this troubleshooting procedure if the blower does not work.
Before doing this troubleshooting, check the gauge control and HVAC DTCs. If DTC U0100 or 10 is indicated, troubleshoot the indicated DTC first.
1.
Dust and pollen filter check:

Dust and pollen filter check
?1.
Remove the dust and pollen filter.

?2.
Inspect the dust and pollen filter.

Is the dust and pollen filter clogged or restricted?

     
YES
     
     
     
     
NO
     
     
     
Go to step 2
2.
Problem verification:

Problem verification
?1.
Clear the DTC with the HDS.


?2.
Turn the ignition switch to LOCK (0) and then back to ON (II).

?3.
Do the Self-Diagnostic Function with the HDS.

?4.
Check for DTCs.
DTC Description
DTC
U128D MICU lost communication with gauge control module
  

Is DTC U128D indicated?

     
YES
     
     
     
     
NO
     
     
     
Go to step 3.
3.
BLOW REQ SW output check:

BLOW REQ SW output check
?1.
Turn the blower control dial to MAX.

?2.
Check the parameter(s) below with the HDS.
Signal
Threshold
Current conditions
Values
Unit
Values
Unit
Blower Request switch
ON
      

Is the BLOW REQ SW on?

     
YES
     
     
     
Go to step 4.
     
NO
     
     
     
Inspect the blower motor.?
4.
Open wire check (BLOWER REQ line):

Open wire check (BLOWER REQ line):
?1.
Turn the blower control dial to OFF.

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

?3.
Disconnect the following connectors.
HVAC control unit 32P connector

?4.
Connect terminals A and B with a jumper wire.
Terminal A
HVAC control unit 32P connector No. 29 (PUR)
Terminal B
Body ground


?5.
Turn the ignition switch to ON (II).

?6.
Check the parameter(s) below with the HDS.
Signal
Threshold
Current conditions
Values
Unit
Values
Unit
Blower Request switch
ON
      

Is the BLOW REQ SW on?

     
YES
     
     
     
     
NO
     
     
     
Go to step 5.
5.
MICU internal open check (BLOWER REQ):

MICU internal open check (BLOWER REQ):
?1.
Turn the ignition switch to LOCK (0).

?2.
Disconnect the jumper wire.

?3.
Connect terminals A and B with a jumper wire.
Terminal A
Under-dash fuse/relay box connector P (24P) No. 21 (PUR)
Terminal B
Body ground


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

?5.
Check the parameter(s) below with the HDS.
Signal
Threshold
Current conditions
Values
Unit
Values
Unit
Blower Request switch
ON
      

Is the BLOW REQ SW on?

     
YES
     
     
     
Repair an open in the wire between the under-dash fuse/relay box and the HVAC control unit.?
     
NO