The BOO switch is not part of the cranking circuit. You can download the Ford disks from Ford Service Manuals - Google Drive and install as described on this page:
(click this text)

But '96-up trucks have a brake-shift interlock solenoid on the steering column, which can either be bypassed as explained in the owner's manual (turn the key to LOCK, shift to neutral, then start), unplugged, or simply removed.
(click this text)

It's #31 on this diagram:
(click this text)

This is the '96 Econoline BOO page. R/LG goes to the MFS for the taillights; C goes to cruise, EEC (for auto trans control), & ABS.
(click this text)

But '96-up trucks have a brake-shift interlock solenoid on the steering column, which can either be bypassed as explained in the owner's manual (turn the key to LOCK, shift to neutral, then start), unplugged, or simply removed.
(click this text)

It's #31 on this diagram:
(click this text)

This is the '96 Econoline BOO page. R/LG goes to the MFS for the taillights; C goes to cruise, EEC (for auto trans control), & ABS.