I am trying to wire in a GE sunsmart 15312 digital timer. The switch I am replacing has only black wires. Two on top and two on the bottom.
The instructions state that some installations have only balck wires but the instructions do not tell me how to install when there are only black wires.

I have a voltohm meter and can make limited circuit measurements like continuity and voltage checks.

Please help. Thanks

Jukebox Bill

Can you give more details of the switch your trying to replace?

It has four wires?

Is is a simple single pole switch, one switch that controls a light(s)?

Could be two wires are the feed, and there are two wires for two lights?

A photo would be helpful.