How do you program a Utilitech #0155671 Indoor/Outdoor timer?

you could try this link and see if it helps you out. How do you program Utilitech 0192773 indoor timer Google Search

Yes but maybe it will not last very long.
Utilitec 0155671 is indoor timer with 2 grounded outlets.
Indoor timers will work outdoors until they gets wet from rain, wet from evening dew, or overheated from exposure to sun.
http://waterheatertimer.org/How-to-program-Utilitec-0155671.html

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

Open following links:

1) Basic written instructions:
http://waterheatertimer.org/How-to-program-Utilitec-0155671.html
2) Instruction pdf manual for identical Woods 59377 timer showing programming plus how to set countdown and random feature, summer-winter changeover, load ratings.
http://waterheatertimer.org/pdf/Woods-59377.pdf
3) More resources
http://waterheatertimer.org/Woods-timers-and-manuals.html#59377

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AM and PM shows on display when programming
http://waterheatertimer.org/How-to-program-Utilitec-0155671.html

Utilitec 0155671 7-day digital programmable timer is sold under different brand names and numbers
http://waterheatertimer.org/Woods-timers-and-manuals.html#59377
Read instructions on following link.
http://waterheatertimer.org/How-to-program-Utilitec-0155671.html

There are 7 general things to look for if digital timer is not working correctly.
1) 0155671 timer is considered incandescent light bulb timer (tungsten) and not necessarily made for motors loads, TVs, CFLs etc. Try using timer on table lamp with incandescent bulb. Turn lamp ON, and make sure bulb is good.
2) Outlet is wired wrong: test outlet with circuit analyzer, and try timer on another outlet, and with different load. For example if outlet polarity is reversed, or if load has interference.
3) Timer is programmed for ON times but not for OFF times.
4) Programming has conflicts, for example program1 ON is for 8am Mon but program1 OFF is for 11am all-days-of-week.
Or program1 and program2 ON-and-OFF times conflict.
5) Timer is not set in AUTO mode, and timer is in random or countdown mode.
6) Timer is defective: 6-8% of all timers arrive defective.
7) If timer is older, the internal battery may be fading. Battery is not replaceable. These timers have 1 year limited warranty.

May 2011: Utilitec 015550 is not enough information to identify timer at this point.
New timers come on the market.
Do one of the following to find best answer

1) Add a comment and describe timer in detail.

2) Add a comment with in-focus photo of timer posted on Flickr.

3) Open following links to identify same-similar timer, and add a comment if needed:
http://waterheatertimer.org/How-to-program-Utilitec-0155671.html
http://waterheatertimer.org/Woods-timers-and-manuals.html

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I have Utilitec 01555671
http://waterheatertimer.org/How-to-program-Utilitec-0155671.html

Which Utilitec timer do you have?

Following page has instructions for 0192773, with links to 0155671, 0144506, and 014124 programmable timers:
http://waterheatertimer.org/Program-wire-Utilitec-0192773.html

Add a comment with your timer ID and I will help more.
If your timer is not shown on link above, add a comment and describe your timer.
I have extensive files on timers.

Westek TE06WHB timer
Utilitec TE06WHB timer
Woods 59377 are identical timers
http://waterheatertimer.org/Woods-timers-and-manuals.html#59377

Woods 59377 manual
http://waterheatertimer.org/pdf/Woods-59377.pdf

Written instructions:
http://waterheatertimer.org/How-to-program-Utilitec-0155671.html

http://www.fixya.com/support/t6839959-bought_utilitech_0155671