Headlight Wiring Modified by previous owner

Hi. First post here and new member. I just bought a 1994 Tacoma base cab 4X4 with a 4 cylinder engine and only 178k miles on it. The previous owner did a lift on the truck and I think he made the brights option on the headlight stalk turn on a set of spots that were removed from the truck before I bought it. My dims work fine but when I go to the stay on bright option (push)the headlights go out. When I flash the lights using the momentary flash (pull) I get a bright filament on the left and the right light goes out.

Does anyone have the wiring diagram for this circuit they could point me to or post by scan? I am handy with a voltmeter but would like to understand the playing field before I start the dis-assembly steps. Thanks in advance.