Originally Posted by Tfryman
Troubleshooting a short as you describe is very difficult and requires both a true schematic diagram as well as a true wiring diagram.
Basically, you need to determine where the half-way point of the circuit is and disconnect the + lead supplying the second half of the circuit.
Stick your fuse in - if it still blows, the short is upstream, if it doesn't, the short is down stream.
Now split the offending half circuit again and test again. Continue half-splitting until you find the problem.
A wiring diagram may not show as installed
. When you find the wire with the trouble is when the real fun begins.
If you have a volt/ohm meter, they cost about $10 at WalMart, try it this way.
Disconnect both wires at the fuse, 1 on the fuse and the other on the ground bus. Test for the short.
If it's gone you get to GO ahha
Then follow Tfryman's instructions, start about 1/2 way from the fuse.
The meter will pay for itself pretty quick.
Good luck and keep us updated