My headlight switch fried and i replaced it with two known good ones and i only get tailights to come on but whats wierd is that the defroster light stays lit on all of them and gets brighter when pushed on, every wiper switch i try only works on 1 speed even ones that i know are good.. Does that small computer looking thing under the dash control any of that because when i unplug the harness the defroster light stays off until pushed. I checked with a meter and have not been able to get power to the headlights. What does that silver box under the dash control? and what should i try next? Im stumped

 

searched some more and found that the little computer is the power steering computer and since i dont use power steering i didnt have the fuse in which leads to a dim defrost light. Im now wondering if other fuses that arent being used are keeping my headlights from turning on so im putting fuses in all empty spots. It couldnt hurt since the ps and defrost share a fuse, maybe the headlights do to.