Ho guys,
I'm new to Arduino, trying first sample project with watering plant.
I'm using Arduino UNO Wifi + Arduino Motor Shield + water pump.
Problem: after couple of adjustments to code the pump stopped receiving power. Pump is connected to group A on Motor Shield. But when connecting power - after one not complete cycle one LED from group B start blinking as well for some reason (which I haven't figured out yet). LEDs on group A are working as before. Also, it seems like brightness of LEDs is reduced big time.
Parameters of pump:
Input: 4.5-12V, 05-5W
I've connected Arduino UNO to USB port to upload code, added standard 9V battery to motor shield.
The pump was working fine at the beginning, but then no power on pump. LEDs are blinking. When I measure Voltage on outputs to pump(group A), measurement is: 4.85V (with 4AA supply through Arduino UNO). But at the same time there is -4.85V supply on group B outputs 
Does it mean I've ruined H-bridge? Or can it be something else, like not sufficient power to run pump, so LEDs are twice less bright as indicators? But why then LED on group B is blinking, even it's not programmed to work?
There is a possibly that I could unnoticeably possibly shortened the GND and Vin. That's all I can think of...
Thanks for any help!