electrical weirdness

[farmmedicoh]

my 85 300SD hasn't been the happiest car of late
some time ago my climate control switches stopped working so i jumped the blower motor to the sun roof power feed and gave it it's own switch
since then things have been acting very strange
my temp gauges skyrocket even though a thermal scan of ALL engine parts says the temp is absolutely fine
my fuel gauge it crammed into the full range most of the time and only goes down to just above 3/4 before the reserve light comes on
when i turn on the high beams both the fuel and temp gauges pin to max and the warning buzzer sounds
i know that i've messed with the sacred oneness of the car's electrical balance, i accept that
apparently while i was mucking about in there i shorted something important
could this be a ground issue?
is there some magical component that ties all these things together somewhere i can't find?
i did try swapping the instrument cluster from my 82 300SD and it did exactly the same stuff
the funny part is that the car seems to run fine
my mileage is a wee bit low (25mpg) but that could be due to some transmission issues i've been chasing for years
heck, i even dropped the $400 on the factory manual
helps me almost not at all
anyone out there got ideas?