Suggest you visit your local public library, and find the Chilton's Repair Manual for the 1999 Ford Expedition. They show the wiring diagram for the ignition coil in the Manual.
P0352 Ignition Coil B Primary/Secondary Circuit Malfunction
On a 1999 Ford Expedition , 4.6 liter V8 engine : It has the Electronic Distributorless Ignition System ( EDIS ) and uses ( 2 coil packs that each have 4 towers for the spark plug wires ) I believe the coil packs are mounted on the FRONT of the engine on each side of the " V "
On a 2001 Ford Expedition : Both the 4.6 and 5.4 have the Coil On Plug ( C.O.P. ) ignition system with ( 8 ) individual coils
firewall 4 - 8 3 - 7 2 - 6 1 - 5 front of Ford Expedition ( 5.4 liter )
Your 2001 Ford Expedition has the Coil On Plug ( C.O.P. ) ignition system so there are ( 8 ) individual coils
The 1999 Ford Exoedition does not have a distributor The 4.6 has the EDIS ( Electronic Distributorless Ignition System ) and has ( 2 ) coil packs with ( 8 spark plug wires ) The 5.4 has the Coil On Plug ( C.O.P. ) ignition system with ( 8 ) individual coils
On a 1999 Ford Expedition : There is no distributor cap The 4.6 has the ( EDIS / Electronic Distributorless Ignition System ) with ( 2 ) coils and ( 8 ) spark plug wires The 5.4 has the Coil On Plug ( C.O.P. ) ignition system with ( 8 ) individual coils
On a 1999 Ford Expedition : There is no distributor ( or distributor rotor ) The 5.4 liter V8 engine has the Coil On Plug ( C.O.P. ) ignition system with ( 8 ) individual coils The 4.6 liter V8 engine has the Electronic Distributorless Ignition System ( EDIS ) with ( 2 coil packs ) and ( 8 spark plug wires )
I'm not a mechanic / technician but on the 1999 Ford Expedition I believe the 4.6 liter was still using the EDIS ( Electronic Distributorless Ignition System ) which uses ( 2 ) coil packs with spark plug wires , where the 5.4 liter has always used the Coil On Plug ( C.O.P. ) ignition system with ( 8 ) individual coils
at each spark plug
On a 1999 Ford Expedition , 4.6 liter V8 engine : I believe the ( 2 ) coil packs ( with four towers each for the spark plug wires ) are located on the front of the engine It has the Electronic Distributorless Ignition System ( EDIS )