Before you attempt any reprogramming, you might be better served by performing a RESET on the clock. TO RESET TIME SWITCH COMPLETELY: Press the recessed RESET switch for
five seconds to remove all eight available events and to reset time of
day clock to 12:00 A.M.
After resetting, try reprogramming again. The procedure below is copied from the manual (which can be downloaded here
TO MANUALLY TURN ON OR OFF: Program Selector switch must be in RUN position. In AUTO or MANUAL Press ON/OFF button. Display indicates load is either on or off.
TO SET TIME: Slide Program Selector switch to TIME SET. Press HOUR and
MINUTE buttons individually to select current time of day. Note that clock is a 12 hour AM/PM repeating clock.
TO SET OR CHANGE PROGRAMMED SET POINTS: Select PROGRAM mode with Program Selector. Note that the event display shows Event #1. There are eight possible programmed events. Four ON and four OFF which are programmed alternately. All available events need not be used.
Press the HOUR and MINUTE buttons separately to program the first ON time
desired. Note the ON indicator (OFF in the next step) will only be displayed after the hour has been selected unless an ON time was previously entered.
Press EVENT button. The display now shows the next Event #2. Press HOUR and MINUTE buttons separately to select first OFF time or Event #2.
Press EVENT button to select Event #3. This is the second ON time. Program the ON time by pressing the HOUR and MINUTE buttons. Repeat this procedure for up to 4 ON and 4 OFF times (8 Events) as required. Return Program Selector switch to RUN Position. Be sure Manual/Auto switch is in the AUTO position.
TO OVERRIDE PROGRAM: Program can be overridden at any time by selecting the MANUAL position. Program set times will be maintained but will not operate the controlled load(s) automatically.
TO CHANGE OR DELETE PROGRAM SET POINTS: Place Program Selector switch into PROGRAM mode. Press EVENT button to step through the eight possible events. Note that the times which have been programmed will be displayed or 0:00 will be displayed if no set point has been entered. To change an event time, press the HOUR and/or MINUTE buttons to change the time currently in the program to the new time desired. Press EVENT button to proceed to next programmed event. To remove a programmed Event: Press the ON/OFF button two times. When this is done, the display will show 0:00 and the event number.
I hope this helps & good luck!