Rear wiper switch re-purpose
 

I installed a Rigid Ignite light where my rear wiper arm was on my 90 4runner. I want to use the rear wiper switch on the column to turn it on. With all the logic/safety features with the rear window/wiper, I am not having any luck. First I thought it would be as easy as unplugging the wiper motor and tapping into power from there. No luck Without it plugged in, no power gets there. I found that power for the rear wiper motor actually comes through 2 alternating lines. One powers up for moving the motor one way, then it switches to move it the other way. If I want my light to turn off and on about every 5 seconds, all would be good. Next idea was to connect the 2 power wires together then connect to light. It would stay on constant, but dim a little bit when power switched lines. Not too annoying, figured it would work, until I discovered that when wired this way, even with switch off, the rear window would not work. I am guessing that the little black box that controls the rear window, also controls the rear wiper. Does anyone know if there is an easy way to just get constant power from the wiper switch on column to the plug at the rear wiper motor?
Thanks

Insert a diode on each power line this will prevent power flowing backwards and should smooth out the light. Part of the wiper logic controls the window, there is a switch that tells it the wiper is all the way raised and safe to move the glass. Locate the safety pins at the wiper plug and jump them each other. I don't remember if that is switched ground in that case it's just one wire.