Check for continuity:
Red wire:
-Put one probe of a VOM (Volt-Ohm-Milliameter) on the red wire of battery connector, and the other one the motor terminal.
-Press the trigger, there should be a continuity.
-If not, there's a problem.
Black wire:
-Same as above, only thing is you don't have to have to press the trigger to check its continuity.
You might also want to inspect the wires for strip along its length. It could also be shorted on the gearbox, check wirings on switch assembly.
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5.56x45mm + m27 = M249(SAW)
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