Would you guys try to repair/splice this or simply replace it?

My passenger side fog light no-workie-no-moe.

As a cheap temporary fix, you could try to just tape it back up, while you search for a new one

Repair. Solder and cover with shrink wrap. Smear Dielectric grease (bulb grease) over wire before covering with shrink wrap. Or use butt connector then cover with grease then cover with shrink wrap. Might have to wrap tape above and below connector to add some meat to the wire in order for a shrink wrap to seal.... you would need to use a wider wrap to slip over the connect

Also pull the wire out of the black covering to make sure there are no other cuts...hidden.

Truthfully, If these are available new, I'd buy two and replace them both and keep the used one that isn't damaged for backup.

Unless, of course, they are priced stupid! Then a decent repair/rebuild.

I'm sure you already know that there are different shrink wrap ratios so you can make tight and hopefully watertight covers for a varied sized components in the area. Up to 4 to 1, I believe.

I hope this helps!

If they were available new I'd buy one ... likely two.

They're not unless one needs the entire fog light assembly and then they're ~ $230/ea.

OUCH! I guess surgery is in order! Gook Luck!

When repairing wires with broken insulators and I do not want to open or cut the wire for a heat shrink, I use silicone tape that does not use glue for adhesion. You stretch it and it bonds to itself and forms a tight seal like a heat shrink. Also I use it to protect wires that are likely to become damaged over time to keep problems from happening. You can warm it up with a heat gun after application. Removing it is not easy like electrical tape
It costs about $1 per foot to get the good stuff so it's not cheap to use.