New Dual XIA3145 2/1 LED glows red, guide claims speaker problem

channel mobil power amplifier hooked to a 4 ohm 10" subwoofer. input is from car radio output.

Status LED glows red "protect" or fault, its supposed to be green, guide claims speaker problem (crossed wires, defective speaker, or improper ohm rating (less than 4ohm load) . Wires not crossed. 4 ohm subwoofer is supposed to be ok for this amp, tested it on 6 ohm speaker, still red. Tested speaker in bridged and unbridged single channel, still red.
Speaker tests ok on another amp.
Amp is no