Amp turns on with the tuner setting and plays, when i switch to ubs mode the amp shuts off

Hello daweeksy115x,

You did not specify your install specifics, but the trouble is probably the head unit "remote turn-on" lead. Some head units will have both a power antenna and a remote lead. If you inadvertently wired the amp turn-on to the power antenna lead, it can cause the problem you described.

If you head unit does not have a dedicated remote lead, the best solution is to wire the amp turn-on terminal to a switched accessory 12V source.

Hope this helps.