CXR5805 CXT5605 and CZT5305 Climatronic Controller display flashing.
Manual Override Switch is set in a mode other than AUTO (Clock symbol)
Reset Manual Override Switch to AUTO (Clock symbol) mode.
Details of this and other Manual Override Switch mode options and associated selection / de-selection may be found in the respective Climatronic User Guides.
CXR5805 User Guide may be viewed here.
CXT5605 User Guide may be viewed here.
CZT5305 User Guide may be viewed here.