amp not powering on

came outside to try the TuN software a bit more and discovered the amp no longer powers on. it was just working last night. on the multimeter, battery cable reads about 12.5. remote wire reads the same and it is coming from the remote out on the FiX. no lights on the amp. FiX and TwK are both powering on. inline fuse on the amp cable is intact.

looking for a few ideas on what to check.

 

Other two choices are ground wire and amp fuses.

 

yea, it was the ground. found a new spot. sanded it way down. amp fired right back up. not sure what had changed between yesterday and today. had me freaking out a bit.