Hi my name isXXXXX to just answer.
When the fuse blows , Yes it means that there is a short to ground in the circuit for the turn signals , if that is the fuse that is blowing. Bulbs will not cause a short, that will blow the fuse.
You need to inspect the wiring from the turn signal switch back to the rear lamps.
Look for areas that have a rub mark on them. Any where it makes a sharp turn, like where the harness passes down the left frame rail near the back of the left inner fender,.
The harness can cut itself on the inner fender and cause a short. Also if there is a trailer plug. Check this wiring carefully, even inside the plug where the wires connect.
Any bare spot can short to ground. The wire colors of the wires you want to check will be yellow( left turn) and dark green (Right turn).
If you need more information on this concern Please Ask.