Electrical Questions? Ask an Electrician Online.
Hi, I'm Mike G and I'll be assisting you. A California 3 way has a hot wire to the common termination on a 3 way and 2 traveler wire on the other terminations at one switch. At the second 3 way the travelers from switch one connect in the same way to the gold screws and the common is the switched hot going to the light.
Give me the model number for verification. In most cases a modification of connections is required.
OK , the yellow connects to a red traveler to the standard 3 way, the blue connects to the switched hot going to the light, the other traveler will connect to both the hot and a traveler termination. The white connects to both the timer white and the fixture white.
That is a Carter 3 way. Hot and neutral at both switches and the common alternates either hot or neutral. You can't use a timer on that.
Only if you omit the operation on one switch. You make the neutral a solid connection and cap the black at the discontinued switch. At the timer connect black, white and blue. Yellow not used. Can't use as a 3 way without traveler wires.