Originally posted by SPL_Eclipse jsut to back that up...it should be the thick one. i think its 12-14 gauge wire. as for running wires through the door, its almost impossible, as we have a solid block of rubber in the grommet.i would suggest "fishing" wires through by taping an existing wire connection to a coat hanger and using that to pull the new wires through, then "re-fishing" the initial wire back through. good luck...i just cut a small slit in the wire loom and ran the wires around the blockage, then sealed everything with electrical tape.