Subwoofer recognizing signal question

My preamp has a y-splitter on the output so that half goes to the amp and half to the subwoofer. When I first turn it on (after a day), the sub will get no signal. I have to turn it on, then turn it off and back on again before there is a "green" light on the sub indicating it is getting a signal. Any idea why this is happening?
 
The splitter sends full signal to both the amp and sub- there is no division.

Does the subwoofer stay silent even when there is audio coming out of the regular amp?
Does the subwoofer have a sleep mode? (auto-on on signal detect)? If it does, there is probably a switch to select between always on and auto on.

When I first turn it on . . . I have to turn it on, then turn it off and back on again before
Which item- are you turning on and off the sub or the pre?