Injecting power into circuit to find a short to ground
You can vary the point of injection to help you locate the position of the short.

Use two probes. One probe injects current. The other measures voltage with respect to ground. Use two so the voltage measurement is not corrupted by the variable drop you will get between the current injection probe and the track.

You can use either (or both) of these strategies. The first is to inject current at some random point, then move your voltage measurement probe around the 3.3v net. Lower voltages mean you're getting closer to the short. The alternative is to probe the voltage at some random point, and change the points at which you inject current. Again, lower voltage measurements mean you're injecting closer to the short.