I actually tapped into my light circuit out under the master cylinder.
On my 86,
light brown for park lights
Solid red was low beam
Solid green was high beam
I know a lot of the colors changed on the 87 model though.
PS if you tap in under the dash, ....wait your dimmer switch is in the steering column isn't it.
Mine is on the floor, I had to go outside to get the low high beam after the floor mounted switch.