[Jackarutu]

Perhaps we better start at the beginning here. What brand Airsoft Replica do you have? Is the wiring original? Has any modification been made to the Replica?

As a general rule:

The positive lead from the battery goes to the lower solder pad on the trigger switch then through the switch housing to the selector switch lowest contact. Then it gets shorted via the selector switch to the upper contact on the selector switch back thru the switch housing to the upper trigger switch solder pad and then to the positive contact on the motor. Thus, if you disconnect the positive motor contact and the positive battery contact and then connect one of lead of your VOM on each end of these circuit paths you should read open unless the trigger is pulled and the selector is in either fire or auto position.

If the selector is in fire or auto and the trigger is not engaged and the VOM shows continuity then you have something weird going on and need to trace it down as to where the switch is getting shorted around. The fact you gave about when you pull the trigger the motor turns faster makes is sound as if you have a "High Resistance short" across your trigger switch and when you pull the trigger then it has full continuity and the full voltage is applied to the circuit.

This could be caused somewhere along the two red wires (battery Positive and Motor Positive) going to the trigger switch getting their insulation damaged and the two wires shorting out but in a high resistance connection which limits the current through the circuit: such as when they get pinched when the gearbox closes on them.

Cheers