Don't install 100W light bulbs w/o using upgraded harness.
Search for headlight wiring harness or go to www.suvlights.com and buy the harness for Toyotas, you need the negative switchable version.
Then you have full power up front. Get the 90/100 W bulbs from www.rallylights.com. Stay away from the fancy blue bulbs. Get the Hella bulbs and they'll last for years. All that for 8.-/piece

92 Xcab V6 4x4 SR5 5sp., Detroit locker rear, lim. slip front, Warn hubs, H4's, electr. fan, eng. oil cooler, 1 lift, open cat.