Could be the one of the blend air motors is faulty. Could also be a blend door has broken. If it has it's a total dash out job i'm afraid.
The system has a self diagnostic function. follow the instructions below to read off any fault codes.......
ENTERING THE AZC SELF-DIAGNOSTIC MODE
To enter the AZC self-diagnostic mode, perform the
following:
(1) Depress the A/C and Recirc buttons at the
same time and hold. Rotate the left temperature control
knob clockwise (CW) one detent.
(2) If you continue to hold the A/C and Recirc buttons
depressed, the AZC control module will perform
a Segment Test of the vacuum fluorescent (VF) display.
In the Segment Test you should see all of the
display segments illuminate as long as both buttons
are held. If a display segment fails to illuminate, the
vacuum fluorescent display is faulty and the heater-
A/C control must be replaced.
(3) After viewing the Segment Test, release the
A/C and Recirc buttons and the display will clear
momentarily.
If a 0 is displayed, then no faults Should there be any faults, all fault codes will displayed in ascending numerical sequence, whether current or historical.
Input faults 01 = IR thermister circuit open
02 = IR thermister circuit shorted
03 = Fan pot shorted
04 = Fan pot open
05 = Mode pot shorted
06 = Mode pot open
07 = IR sensor delta too large
08 = Reserved
09 = Reserved
10 = Reserved
11 = Engine air intake temperature Buss message
missing
12 = Country code Buss message missing
System Faults 13 = Mode motor not responding
14 = AI (Recirc) motor not responding
15 = Left temperature door not responding
16 = Right temperature door not responding
17 = Mode door travel range too small
18 = Mode door travel range too large
19 = AI (Recirc) door travel too small
20 = AI (Recirc) door travel too large
21 = Left temperature door travel too small
22 = Left temperature door travel too large
23 = Right temperature door travel too small
24 = Right temperature door travel too large
25 = Calibration check sum error
26 = Engine coolant temp bus message missing
27 = Vehicle speed bus message missing
28 = Engine RPM bus message missing
29 = OAT bus message missing
30 = Display intensity bus message missing
31 = VIN number bus message missing
32 = Reserved
Historical fault codes:
Input faults 33 = IR thermister circuit was open
34 = IR thermister circuit was shorted
35 = Fan pot was shorted
36 = Fan pot was open
37 = Mode pot was shorted
38 = Mode pot was open
39 = IR sensor delta was too large
40 = Reserved
41 = Reserved
42 = Reserved
43 = Engine air intake temperature Buss message
missing
44 = Country code Buss message missing
System Faults 45 = Mode motor was not responding
46 = AI (Recirc) motor was not responding
47 = Left temperature door was not responding
48 = Right temperature door was not responding
49 = Mode door travel range too small
50 = Mode door travel range too large
51 = AI (Recirc) door travel range too small
52 = AI (Recirc) door travel range too large
53 = Left temperature door travel too small
54 = Left temperature door travel too large
55 = Right temperature door travel too small
56 = Right temperature door travel too large
57 = Calibration check sum error
58 = Engine coolant temp bus message missing
59 = Vehicle speed bus message missing
60 = Engine RPM bus message missing
61 = OAT bus message missing
62 = Display intensity bus message missing
63 = VIN number bus message missing
64 = Reserved
65 = Reserved
66 = Reserved
67 = Reserved
