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1) Did timer work before and stop working?
If timer stopped working, then buy another one for $15.
2) Is this a new timer?
Is the wiring correct?
Does the on-off switch turn load on and off?
GE 15068 is countdown timer.
Following link has a photo showing example timer:
http://ecx.images-amazon.com/images/I/311ev7wNxkL._SL500_AA300_.jpgTo operate countdown functions, move slide switch to Timer.
Rotate dial to one of the numbers shown on dial, for example 15.
Timer will turn on Load.
Timer begins counting down for 15 minutes.
When countdown expires, load turns off.