A good old possibility in random fuse blowing situations is the car nudging ckt or the buzzer since it is not a regular occurrence. In some cases you may need to pick up some in line fuse holders at your local Radio Shack. Separate your P24v bus into just a few wires per fuse holder and slightly under fuse each branch as to not blow the P24 fuse first. At least then you can determine a direction for what is blowing. Good luck.