Blowing fuse for tail lamps, side markers and dash cluster???

[transam]

I noticed my taillights were not working and my side marker lights and also my dash cluster lights. I went under the dash and found a 20amp fuse blown. I changed the fuse, turned the light switch on and no side markers, no tailights and no dash cluster lights. I went back under and the fuse was blown again?? Any ideas on where I should begin to look. I have headlights and directional lights and the four way flashers work. I opened the drivers side panel and disconnected the rear harness, I installed a new 20a fuse, reached up and flipped the headlight switch and watched the new 20a fuse just melt in half??So do I assume that the rear end lights are all OK and where do I go from here. I really do not want to try and take the headlight switch as it is a pain to get the switch panel out of the dash? I did install a brand new front lighting harness and all new bulbs up front?? What about the brake light switch being shorted, as I also have no brake lights???

 

[Ricks72Chlgr440]

What have you done to the car recently? Perhaps a wire got pinched or something was installed that damaged a wire. Like Kat said, disconnect the connector for each light then see if the problem persists. If the fuse does not blow start reconnecting one at a time until the fuse blows. That should point t you in the right direction.

 

[Challenger RTA]

Behind the drives kick panel. Unplug the rear harness. That will narrow it down where it's at. Use a lower amp fuse 5 or 10, if you run out or save the 20 amp for when you need it.
Inspect the light sockets there might be a bad one.

At the rear harness plug a test light can be used to see if there is a short to ground. Unplug all sockets and remove all bulbs. Be sure to there not touching ground when out. Use a test light connected to power and touch to each connector. If it come on that's where the short is. If not found plug the just the sockets in no bulb. Check again. Don't forget about the dome light.

Thought I had a picture of the bad socket. This is after I fixed it.
The plastic insulator was cracked it's what caused my issue maybe as yours