Parking/taillight fuse burns out

Here is an easier approach. A simple trick to finding a short is to replace the blown fuse with a pair of spade terminals, then use small jumper wires to connect them to a twelve volt light bulb. A brake light bulb works well. When the circuit is live and the short is present, the bulb will be full brightness and hot so be sure it is not laying on the carpet or against a plastic door panel. Now you can unplug electrical connectors and move things around to see what makes the short go away. When it does, the bulb will get dim or go out.

You are not likely to find the cause of the problem under the dash where everything is protected. Better suspects are crushed wires in the trunk, chewed-up trailer wiring harnesses, and problems in bulb sockets. I have also found a few pinched wires behind tail lamp assemblies after someone spliced in trailer wiring to those wires. Those do not show up right away. It takes some time for screw's threads to work their way through the wire's insulation and cause a short.

Thanks! That is an excellent suggestion. I will be working on this car soon and will report back on how well this works and (hopefully) where the short was found.