There is a light on the outside of timer should it stay on all the time

1) Time master is sometimes the same as Intermatic EJ351:
Copy following link to identify timer:
http://waterheatertimer.org/Intermatic-timers-and-manuals.html

2) Add comment and describe timer in detail, and/or include photo of timer so expert can identify timer.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Adjust the timer setting under the sensor it might be set to zero you shuld adnust to about 3 minutes or desidered time if set to minimum light will stay on if this does not help change unit its faulty

Just plug it in and use the button to select 1-thru-8 hour run time.
N1505 and similar timers appear on following links.
http://waterheatertimer.org/Woods-timers-and-manuals-old.html#N1502
http://waterheatertimer.org/pdf/Woods-N1502-manual-english.pdf

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Here's what I found.
Pull up all of the little pins around the dial.
Push down all pins for the time that you want the light to stay on.
Leave pins up for all time that you want the light to stay off.
Rotate the dial to the current time of day.
Plug timer into wall.
Plug light into timer.
Ensure light is ON.
Gary

From the description you gave on your post , sounds like you hooked the timer up correctly . Again , from the panel the hot ( black ) is jointed with the blacks feeding the inside switch and the timer correct ? And the Neutral ( white ) is jointed feeding the inside lights and timer for outside correct ? And from the timer ( GE model 15086 ) the Red Wire ( Switch Leg from timer ) is connected to the Black ( Switch Leg ) feeding the outside lights correct ? If this is exactly how you've wired your timer , then you have done your homework . Now all you need to do is make sure you have programed your timer correctly , and with your instructions that came with the timer , this should be no problem . If you continue to experience trouble , my suggestion would be to return the timer . It's not unheard of for some of these timers to come from the factory defective . This wiring configuration should not affect your inside lights . I hope this helps your home wiring project . I'm an electrician if that's any consolation !

There are two things you can check outside before calling a service technician. The first is the breaker to the outside unit. There is a breaker or disconnect near the unit. If there is nothing wrong with the electrical supply, check the refrigerant level. If the level is low, the pressure switch will cut off power to the compressor to protect it from damage. DO NOT try to recharge the compressor yourself.

I see nothing in the manual that says 'outdoor use only' EXCEPT timer runs on photoelectric eye.
Timer turns ON automatically at dusk, so if timer is inside, and indoor lights are ON, then timer stays OFF.

http://www.intermatic.com/~/media/files/intermatic/products/instructions/timers/hb51rc%20-%20english.ashx

http://www.intermatic.com/products/timers/consumer%20outdoor%20timers/electromechanical%20timers/hb51rc.aspx


To use timer outdoors.
Plug timer into wall.
Timer turns ON automaically at Dusk.
Rotate dial to set how long timer will stay ON.
Set timer to turn OFF 2 4 6 8 Hours after dusk
Set timer to turn off at dawn
Set timer to ON so lights are ON full time
Set timer to OFF so lights are off full time.

The dawn to dusk feature is activated by photoelectric eye that senses when it gets dark.
If you put timer in a dark room, it will turn ON ... let's say to operate Christmas tree after you leave a room for the evening.
But if room stays dark, the timer will not sense when to turn off unless you also set timer to turn off 1-9 hours after ON.
That being said, a Christmas tree might make too much light for the timer's photoelectric eye.
Make sure photoelectric eye is turned away from direct light.

There should be 2 trippers for each day, the trippers slide on the outside of the dial and would point to the time of day you want your lights on and off. The silver trippers may be gone on that aged time clock, but are easily obtainable.

manually turn the dial pass the red pointer. that shoudl shut-off the light.
if not, you have a defective timer.
if it does. follow the instruction set the gree pointer for the time to turn-on and set the red pointer to the time off.
turn the dial one or more revolution till the arrow head in the center align with the time of day in the center windows.