I am trying to diagnose a 2007 Ford escape that blows its F4 ignition switch fuse when the key begins to turn. Since there is no power to the pcm my obdII scanner is of no use.

Are there any scanning options for the key NOT on position.

Thanks

 

None that I know of.
The way this should be checked is with an electrical diagram to see just what is powered when the key is turned on.
If no diagram is available, then you need to start disconnecting things like radio , ignition, computer, and any add on accessories etc until when you turn on the key it no longer blows the fuse.That is the hard way, but if you have no choice , that is what might be required. A circuit breaker placed in the place of the fuse will prevent having to go through lots of fuses.

A side note,,,,,,,,,,, if you have the owner's manual, it will tell you what circuits that fuse protects and that can save you loads of unnecessary work and time.You confine your checks to those items only.