How to Enter Diagnostics Using Control Head

ENTER DIAGNOSTICS
To enter the diagnostics, perform the following:
1. Depress the A/C and RECIRC buttons simultaneously and hold. Rotate the control knob clockwise one CLICK.
2. If you continue to hold the A/C and RECIRC buttons you will see the display completely light up. This is the Segment Test.
3. After viewing the Segment Test, release the A/C and RECIRC buttons. This will put the test selector at 00, the Select Test level.

At this point a number of tests can be performed. However, the Fault Code Diagnostics should be performed now.
Fault Code Diagnostics