Rob, one method for finding a short that may help you is as follows.
Rig a 12v test light in place of the fuse and when the circuit is "shorting" the light will be on.
Then examine the wiring for that circuit to find where the short is.
When the light is "ON" the fuse would be "BLOWN", when the light goes out the fuse would not be "shorting".
Saves fuses while you're tracking down the "short"
