Need directions for...
 

alternative to a failed head light/ switch. It's an old pickup and the replacement is nearly 300 bucks. I think I may have to splice the headlight wires and use a toggle switch or something similar.

Can anyone outline some directions to help me out here?

What truck? Maybe someone can locate a wiring diagram.

89 Mighty max. I can find the wires by looking on the rear of the bulbs. I'm just wondering if a toggle switch with a fuse link between it and the battery will work. What do you think of this idea?

I would identify the headlight relay or install one. There may be two separate relays for left and right. You don't want that much current running through a toggle switch into the cabin.

Don't forget that you'll need to address the tail lights too. Those are usually on the parking lamp circuit. A wiring diagram will be helpful.

Just looked up the headlight switch for your truck. That is insane. I balked at a $70 headlight switch/turn signal stalk (new) from a Maxima to use in my Nissan Hardbody when I installed fog lights.