tail lights

I have a 93 silverado and have had some light problems in the past. It has one of those panic buttons on the dash and a black box stuffed up
under the dash,When I bought the truck a year ago none of my lights worked in the back,Afriend of mine came by and in ten minutes had them all working,never did tell me what he did and is now unavailableto me . My question is this can I unhook the box under the dashand if so how do I wire the lights door locks horn and etc.? thanksfor any help PRATTFAM
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.