After a recent theft, I will be installing Jimmi Jammers for the door handle and key core for the doors.
I'd like to install a kill switch, and to keep it simple plan on doing: 25a killswitch on fuel inertia switch, 25a killswitch on PCM/Ignition Module fuse

The fuel inertia switch seems easy, cut one of the larger gauge wires, splice in the switch in-between, mount discrete.
The PCM/Ignition Module is a bit tougher, trying to find the right colored wire, but brought in a bigger question - is there an issue with having the PCM disconnected?

Idea is to have both switches in the correct positions, or no start.

 

Inertia switch cut off is fine, you also need an inline fuse on added wires

You can power on the whole engine system, including the PCM, by putting jumper wire from battery positive to any red solenoid or fuel injector wire in engine bay

Fuse 19 in cab fuse box, 25amp, powers the spark coil pack and PCM relay, its powered on by ignition switch
You could replace it with a switch/fuse
That would prevent PCM or coil from powering on

The issue with manual switches is that you HAVE TO turn them off before you exit the vehicle, and you will forget, 100% chance of that
Relays are automatic switches, they go off when there is no power, i.e. key off
So think about doing relays with on BUTTON trigger, so it automatically reset to OFF when your turn off the key and lock vehicle, can not Forget that type of system



Other things
Key release Parking brake, you can set the e-brake but need a key to pull out release handle

Shift interlock disable, automatics with column shifters have a lock that holds the shifter in Park unless foot is on the brake pedal, you can put that solenoid on a switch so can't shift out of Park unless switch is on and foot is on the brake

Flasher relay on automatic start up
4-way flashers are triggered on engine start up and must be deactivated by a switch each time, hide the switch

Time delay fuel pump deactivation
Thief can start vehicle and drive away, but 2 minutes later fuel pump shuts off, OUT ON THE STREET, stalled where all can see and stop to help out the poor guy, lol, like maybe the cops
A thief will defeat most security systems if given enough time in a PRIVATE location
When the stolen vehicle stalls in a PUBLIC place a thief will not stick around to see whats wrong

 

Is the inertia cut-off fused anywhere else? I have an inline but want to be sure if I need to troubleshoot down the line.
I placed the k/s in the glovebox that can only be activated by feel, I'm starting to question if the secondary switch is worth it/necessary.
Do you know the wire color for fuse 19?

The relay is a good point, I will have to reconsider the momentary on. Got to contemplate the wiring for it, too.

 

Fuel pump fuse in engine bay fuse box is the only fuse for the Fuel Pump power

Battery positive-----FP Fuse--------------FP Relay-------------------inertia switch----------------------------------------Fuel Pump-----ground

Light green/purple wire from ignition switch to fuse 19 in cab fuse box(powers 3 fuses, 11, 15 and 19
Red/light green wire out of fuse 19 to spark system coil and to activate PCM power