Why wont 4 ch. amp turn on?

I have a brand new 4 ch. JBL Amp which to be hooked up as my second amp in my car. The first amp turns on right away when my headunit turns on, but my second amp doesnt power on. I Connected the power to the same block the subwoofer amp is on, connected the remote wire to both the subwoofer remote wire and the headunit in 1 crimp sleeve. BUT DID NOT ground the 4 ch. amp, because i want to see if it works before i drill a hole in my car. The 4 ch. amp is brand new, never been used. could it be possible that it wont turn on because its not grounded? Cant think of anything else.