Solid red Light On my amplifier!?

i have a mutant x amp and sometimes it works fine... (solid green) but then im driving along and suddenly the whole music turns off! i look at the amp and its a solid red light... if i turn the amp off and then back on it goes green... then driving down the road 5 min later the same problem happens! ive got a battery tester and it sais that my battery is 100% charge so it should be getting enough power!! i really need help! do i buy a new amp?