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?

__________________
1985 MB 300SD
1982 MB 300SD
1977 Jawa 634 California w/ sidecar

Sounds like you damaged a shared ground.


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1985 300SD
1983 300D
2003 Volvo V70

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by "shared ground" i presume you are referring to the 3 bolts set into the frame behind the instrument panel with about 6000 wires coming into them?
i take it the solution to the problem would be to carefully take apart each bolt and clean the terminals?
i have been thinking it's a ground, but those common/shared ground bolts "look" fine
a case of looks being deceiving?
i'll pull them apart
thx
will advise

__________________
1985 MB 300SD
1982 MB 300SD
1977 Jawa 634 California w/ sidecar

Have you tried undoing what you did to the blower/climate control to see if things return to normal?

It does sound like a grounding problem though.

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82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

i did not undo the "fix"
tomorrow is my day to dive into the dash
i'll try that first
thanks for the reply

__________________
1985 MB 300SD
1982 MB 300SD
1977 Jawa 634 California w/ sidecar