1991 Dodge Caravan: Where do the wires run for brake lights?

1991 Dodge Caravan: Where do the wires run for brake lights? Everything in my 1991 Dodge Caravan mini-van has worked perfectly until yesterday afternoon. I installed a ladder rack on top of the van, and installed a shelfing unit on the floor in the van, running along the left side of the van. After installing these two items successfully, I jumped in the van, put my foot on the brake, and the fuse blew, as well as several others. My question is, where does the wiring in this van run? Along the ceiling under headliner? Through interior of van under carpeting? It pretty obviously I hit a bundle of wiring when attaching either the shelfing or ladder rack. Its going to be alot of work removing what installed, so hoping I can determine where the wiring runs? Thanks!