Climate control flashes the display or the LED lamps when it detects actuator and other faults. Actuators are the things that open and close vents and flaps inside the dash.
The system has a self-test. It can be done at any time (engine running or not, etc).
Push OFF/AUTO and DEFROST simultaneously. Release them and (within two seconds) press A/C .
Error codes found during that test as well as any error codes stored in memory, found during normal operation, will be shown.
To exit the test mode, press the COOL button.
there are about 15 possible error codes.. 01, 02 up to 15.
88 means no faults found. (I think 09 and 10 are the same as 88 unless they appear along with other codes.)