MAJOR Rear wiper, turn signal, abs light, & brake lights issues

Really need some help! I own a
2002 GMC Yukon SLT (flex-fuel)
5.3L V8, 4 door with 4WD. I
purchased my SUV in April of
2017, with 251,000 miles. Within
about 2 wks of having my truck,
the problems started. 1st issue,
my brother & I stopped at a gas
station. I turned the truck off, paid
for gas, pumped, got in, tried to
start it, and nothing: no crank, no
start. My brother thought maybe
something was wrong with the
security bypass from the remote
starter, so he completely
disconnected the entire remote
starter. Tried to start it again,
same thing. After troubleshooting,
the only way I could get the truck
to start was my brother pulled the
starter relay out under the hood, I
got in driver's seat, turned the key
to the start position, he put the
relay back in while key was in
starting position, and it fired right
up. This would randomly happen,
but we were able to get it started
the same way each time. Every
time it happened after that, I was
able to get it started the same
way, but each time it would take a
little longer. I took the truck in to
have it looked at, a few corroded
wires were replaced, a bad ground
was also replaced. The day I
picked it up, I ran a few errands,
and was on my way home when
the next problems started (not
sure if whatever the mechanic did
caused these new problems or
not, but I can't afford to keep
taking my truck to be fixed, I'm a
single mother and I don't have the
extra money to blow). It was a
warm, sunny day. I stopped at a
red light, and all of the sudden my
abs light came on, then the brake
light came on, then the abs light
went off, and the brake light went
off. About a minute later, the
same thing: the abs light came on,
the brake light came on, the abs
light went off, and the brake light
went off. I thought that was weird.
It kept doing it until I came to the
next red light. I stopped, turned
my left blinker on, and as soon as
the blinker engaged, both the abs
light & the brake light went off and
didn't come back on. BUT then,
immediately, my rear wiper motor
turned on, and the rear wiper just
started wiping. After that, the abs
light & brake light didn't come
back on at all, but the rear wiper
just constantly wiped. Few
minutes later, I noticed the rear
wiper had finally stopped wiping,
but I kept hearing a clunking
noise. I parked, went around to
the rear of my truck, and the rear
wiper motor was still engaged, yet
it wasn't wiping; the wiper would
start to go up just a little (it didn't
go up far enough to be seen in the
rear view mirror from the front
seat), it would stop, the wiper
would go back down to the
normal "sitting position" - if you
will, and when the wiper would hit
that "sitting position", thats when
I'd hear that clunking noise (the
noise is normal, it does that when
going back down when the wiper
was working normally).  Nothing I
did would stop this from
happening, it was constant. Well,
the only time it did stop
completely was maybe 3 or 4
times while I was coming to an
intersection, as soon as I hit my
brake pedal, the wiper would stop.
But within about 10 minutes,
touching the brake pedal didn't
make a difference; after that, the
wiper motor was constantly
running, with the wiper going up a
little, stopping, then going back
down. I turned the actual rear
wiper switch on the dashboard to
see if the wiper would actually
wipe, and it did wipe the entire
window Everytime I turned the
switch on. But as soon as I turned
the rear wiper switch off, it was
back to the wiper motor staying
on, wiper going up a little then
going back down. I finally had to
remove the rear wiper fuse, and
that did the trick: the wiper motor
shut off, and the wiper stayed in
place. Over the next wk or so, it
rained a lot. I put the wiper fuse
back in, and the same problems
arose: wiper motor stayed on,
wiper went up and back down,
and just repeated until I removed
the fuse again. It is now months
later, and I still have no use of my
rear wiper unless I put the fuse
back in, but the problem still isn't
fixed, the wiper still goes up a
little then back down, and the
wiper motor will not shut off. As
for the issue I talked about earlier
with my truck not starting, I did
finally get that figured out and
fixed (the solenoid on the starter
died). But as for the rear wiper
issue, that still is not fixed. Also,
I'm unsure if this has anything to
do with it, but the illumination
lights on the dashboard on the left
side of the steering wheel (where
the 2wd, 4wd switches are, along
with the headlights knob, fog
lights knob, and switch for the
rear wiper as well) randomly go
out/turn back on when hitting
bumps, etc. I just need some help
here, winter is approaching and I
need to be able to use my rear
wiper without the motor being on
24/7.