Have a similar question to the others asked about the GE Smart Digital Timer 7 day timer model 15086. I originally got the wires connected but the exterior lights remained in on position. The manual override switch would not toggle from on and off. Also, in continuing to trouble shoot, the ground wire in the wall broke and I don't think I will be able to connect the wall ground to the switch green wire. Can someone please advise on a recommended solution? Thanks!

Wiring instructions and on-line manual appear on following link.
http://waterheatertimer.org/GE-timers-and-manuals.html#15071

I have tested this timer, but I'm not there to test it out for you.
Let me offer a troubleshoot list how I would start.
1) Switch located behind timer door that says OFF-TIMER. Make sure it is set to Timer.
2) 4 square buttons located behind timer door that sit in each corner. These are override buttons, and should turn lights on-off. Push each one separately.
3) Check wiring against instructions shown on link above. This timer will not operate unless wired correctly.
4) Ground wire broken off? Each cable that enters a box can be pulled a bit further so maybe you can grab some of the ground.
The ground is not critical for timer operation -UNLESS- you are using it to power electronic clock inside timer.
Normally white neutral wire is used for clock electronics, as described in wiring instructions.
5) Conflicts in programming. If 7-day programming has conflicting days or hours, timer will not operate as expected.
Check programming.
6) Reset timer and start over.
7) I test timers, and some arrive defective. GE makes a good timer, manufacturing timers for many decades: 15086 is sold at Home Depot. Buy another one and take back defective one.

Add a comment for more free help.
Also take advantage of fixya expert assistance live.
For a price, expert works with you while you work on timer or any do-it-yourself project.
Fixya is always less expensive than a service call.