Wiring - Oil pressure light

[burro_gordo]

First time poster here-
What is the best way to fish a wire from under the rear seat into the engine compartment? At some point in this bug's life, the wire from the Oil Pressure Light was lost.
Here's what I know:
Somewhere between the engine compartment and under the rear seat, all* of the wires have been cut and replaced with white wires. *all except the Oil Pressure Light wire.
There are 7 wires in the rear, only 6 out of the firewall.
Best I can tell, the blue Oil wire makes it to the rear.

03/19/2024 Update:
I was able to fish a new wire through the body using some #12AWG Solid wire as a 'fish tape'. I went in from the engine compartment and down to the access hole inside.
Thanks for your comments!

[busman78]

Use one of the white wires to pull a string back into the vehicle, best way is to solder or crimp a wire to the pull wire, don't want is breaking off half way through. Attach the wire or wires you want to go back to the engine compartment and use the string/wire to pull them through. Be a good time to do a little wire color coding.

[slayer61]

[burro_gordo]

Update:
I was able to fish a new wire through the body using some #12AWG Solid wire as a 'fish tape'. I went in from the engine compartment and down to the access hole inside.
Thanks for your comments!