Just bought a dual VNH2SP30 motor controller and assembled. Ensured I got capacitors right way around (short leg negative to square solder pads).
I have connected a fully charged 2s lipo to vin and gnd. I have not yet hooked up any motors or signals.
The least I would have expected is a power led lit? Any ideas gratefully received, many thanks.
That controller does not have an LED that indicates whether or not motor power is supplied. The LEDs that are on the board indicate which direction the motor drivers are commanding the motor to turn. To use them, you need to send the board logic signals in addition to supplying motor power.
By the way, you can see a schematic that shows all of the LEDs for that board at the bottom of its product page.