The dash lights feed off the tail light circuit, and the tail light and brake light circuits are shorted together. There's two common causes of that. One is a trailer harness that is chewed up and some wires are touching. The other is the wrong light bulb in the rear. An 1157 brake / tail light bulb has two contacts on the bottom. An 1156 has one contact that will short the two circuits together if it's placed in an 1157 socket. Most cars went to bulbs with plastic bases that can't have the wrong one installed, so that leaves the trailer harness. There's also a ground wire in a trailer harness, and bare wires touching that one would cause a fuse to blow.
If you don't have a trailer harness, inspect the wiring inside the trunk. Look for any wires that are chewed up or have bare spots.
Thursday, June 5th, 2014 AT 1:13 AM