I have a 1997 XLT 4dr, 4WD Explorer with 5-spd manual. It has been
essentially trouble-free for almost 250K miles and we've routinely used it
to haul a utility trailer. It came with trailer-prep, so when it was brand
new I had picked up a Hopkins trailer adapter that plugged into the wiring
harness under the left rear of the vehicle and everything always worked
well. This past weekend we hauled my son's furniture home from college after
graduation and the next day made several trips to a storage facility to
store things. After the last trip, we smelled an electrical burn when
pulling in the driveway and found the trailer wiring pigtail (from the
hopkins "T" to the trailer plug) was fried. I unplugged it from the trailer
and parked the trailer. The truck and all lights were working fine, so my
son drove it on to work that evening and returned home afterwards. I had
tried to pull the fried pigtail from the hopkins T, but it was stuck, and
since my son needed to leave we just left it, thinking there was a short on
the trailer somewhere.

Today we found the truck battery dead, really dead, like less than 2 volts.
We tried jumping it, but the jumper cable got hot enough to melt the clamp
insulation, so we pulled the battery and replaced it with a fresh battery.
The replacement battery voltage dropped from 12v to 5 volts in a matter of
seconds and, again, the truck wouldn't turn over. I removed the Hopkins T
from the connector, but the same symptoms exist. No fuses have blown. I
looked at the Auxiliary Relay Box #4 above and in front of the rear wiper
fluid box, but none of the wiring is obviously stressed, and it is not
obvious how to open, or drop, or otherwise get into the box to pull relays.
Any ideas? This has me somewhat dismayed and alarmed at this point.

=Vic=
Bear Gap, PA