Moin, I’m trying to make it short. Car system retrofitted,2 boxes running over a small amplifier and a bassbox that also has its own amplifier. Suddenly, the fuse burned through in the thick + cable seat. Both amplifiers no longer switch on after renewing the fuse. Have dismantled all boxes and chinch cables, it’s just mass, + cables what comes from the battery and a remote cable what comes from the radio. Ignition is off, remote has k a 12 volts only the thick + cable has power. If I turn on the ignition, I have 12 volts on the remote cable but only 5 volts on the thick red cable ?!?!? Measured directly on the amplifier, but before the fuse on the thick red cable I have 12volts, as if the fuse does something but can’t. With the other amplifier exactly the same problem only here I measure instead of 5 fills only 1 volts