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I don't know why the meter blew on your motor. This PWM should be fine, the description rates it at 60 amps continuous and your motor is only 48 amps maximum. The 100 amp maximum draw on this PWM is only for a very short period of time, not 100 amps of continuous use.
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There is no way to know why the "meter" stopped working without troubleshooting it, but I think I know why. SWAG: The PWM cannot increase voltage, but it can reverse it. The meter, which is cheap junk and probably not polarity-protected, is normally connected to the battery input leads before they go thru the wafer switch, so it may not (probably won't) handle reversing the input power polarity externally with the PWM. Not sure what you did with the switch; I'm guessing it was either set (or defaults with no switch) to reverse, and the reversed DC input killed it.
This is why I disconnected the meter on mine, along with all the control/speed coil wires, and wired directly to the main wires going down directly to the motor. Not sure why you don't do this if you are going to use a PWM.
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