1997 Chevy Silverado Tail Lights

I have a 1997 Chevorlet Silverado Z71. I have had problems for about a year and a half now. I bought the truck when I was 2 years old. Who ever owned the truck before me had a electric brake system for trailers installed. I started having problems when the truck started blowing fuses. I then took the electric brake box and wiring out the truck. I didn't unwire anything, everything was just joined together with what I call scotch locks, they are the connectors that you just slide your wire in one side and the oher wire to the side and close the top and snap it down.
I have blinkers and I have a third bake light which is working. I looked at one question where a guy had the same problem but you told him to find the white wire that had been broke. I found a white wire in the rear of the truck, by the taiil light harness. It was just cut and was taped up. I tested the wire and it is the brake light wire, but when I tried to tie it into the tail light harness everything worked. But when I pushed the brake pedal the dash lights came on. So I turned the head lights on and tried the brake lights because I knew there was a problem when the dash lights came on. The brake ligh would not work, well I guess they were working but they should change when you have the head lights on and push the brake pedal. I guess my question is where would I tie this hite wire into the harness. Or where does the white wire go. I can not find a place even on the harness where the white wire would have been. I just have 4 wires, none of them are white?

Thank You very much!
Ryan Jones