70 Challenger SE. I still have tail lamps but the 4amp fuse running the dash lights blows immediately. Any places that are the usual suspects? The problem started when I moved the main dash feed wire from the starter relay battery terminal to a terminal block fed straight off of the 1 wire alternator. I used a 14 guage fusible link. I wanted to eliminate any voltage drop to the dash harness. I've moved the feed wire back to the relay battery terminal but this made no difference. This may be a coincidence, but before the problem began, I had also changed my high beams to a relay setup with the high beam feed feed wire from the dash closing a relay then going to ground. The high beams work just fine.

you might start by removing the high beam feed wire to the relay & see if that stops the dead short from happening