Fuse #13 in engine compartment keeps blowing

It sounds like the ECM is shorted out and you need a used or new one. I would send it out to have it rebuilt.

Check ebay most of our guys use services from there. Also you might want to open it up to check for water damage in which case it may be junk

Did you try my suggestion of replacing the fuse with a light bulb?

You've been replacing a fuse, so you know where it is. Put a light bulb in there instead of a fuse. A typical brake light bulb will limit current to around one amp so the wiring will be protected. When the circuit is turned on and the short is present, the bulb will be full, normal brightness. Hang it where you can watch it while you unplug stuff and move wiring harnesses around. When you do anything that removes the short, the bulb will turn off or be dim. In some cases, depending on what else is in that circuit, the bulb may only dim a little when the short is removed so you have to watch closely while you move stuff.