because there is a short in the wiring, quite common with taillights. The short is often, though not always, right around the taillight area, but can be difficult to trace for a novice. Check areas where the wiring bends around or goes through metal brackets, or even the back of the taillight, etc., looking for a spot where the insulation has been rubbed off by friction.
Short in the wiring or the lamp holder for the tail light is corroded.
Short in the wiring, or the circuit is overloaded.
no i did not replace head light switch
why does my turn signal light keep burning out and why is the sockets and plastic lens melted.
Short in the wiring or one of the bulb receptacles.
you could have a short between the two.
Somewhere between the fuse and the bulb
short circuit on trailer light wiring
A short in the wiring.
Dead short to ground in either: Parking light socket or wire to Tail light socket or wire to Dash panel lights Remove 1 bulb and/or socket at a time to try to determine which is bad
A short in the wiring (grounding out)
Try looking at your tail light socket if it is fried that will blow the fuse