It's possible that your problem could be caused by a number of different issues. I'd first check the awning arms to make sure the tension screws are loose and that the arms are not bent or off center. That could be putting the "maximum load just before the fuse blows" on the circuit as the awning retracts and "at the moment it stops, causes that load to 'just tip the bucket"...
In the meantime, replacing a fuse (while trying to troubleshoot and repair the problem) can be very frustrating... You might consider getting a "blade type circuit breaker" to replace the fuse until you find the issue and repair it. You can avoid much of the frustration of replacing a blown fuse with one of these:
https://www.amazon.com/ZOOKOTO-12V-2...0415353&sr=8-4