1995 Cadillac Eldorado ignition won't turn over

Okay I have a 1995 Cadillac Eldorado no
Heating and Cooling my heater doesn't work
Mike my cooling doesn't work my AC so I
went to maybe check the fuses underneath
the hood of 40 amp fuse was burnt that I
don't know the numbers but it was related to
the cooling so I went to replace it and put
another fuse in there and it popped as soon
as I touch the terminals with the fuse where
the fuse goes the next day I haven't driven it
yet but the next day I go to turn the car over
all the lights come on everything works
except for the car turning over way back in
the back future or you know before all this
happened my cigarette lighter was replaced
somebody hooked up for me but didn't do a
good job to wear the cigarette lighter never
work again so I was told maybe that was the
problem electrical problem something
across for touching so I cut everything out
and disconnect the battery this time put
another fuse in there for the heating cooling
and soon as I hook the battery terminal up it
sparked and blew out the fuse again what
do I do what's the problem somebody told
me there's a fuel shut off electronic fuel shut
off something to check that what do I do
please help me