Syren 10 A motor driver stopped working
simulate this circuit &ndash; Schematic created using CircuitLab

Figure 1. Incorrect and correct current measurement techniques.

Connecting an ammeter as shown in Figure 1a may result in destruction of the driver or the ammeter or both. High quality multimeters are fused on both low and high ampere ranges. If you are replacing the fuse then be sure to use the correct version specified by the meter manufacturer.

The driver datasheet says it is short-circuit proof. If so it should have survived but maybe not. There is no schematic on the datasheet and I can't see any big switching transistors or chips that look like they could handle 20 A so maybe they're mounted on the back of the board. As a result I can't comment on the possibility of repair. You might have to write this off as an educational cost!