The factory radio/cassette player was recently replaced with a new
Pioneer unit. I now have an apparent grounding problem that is driving
me crazy. My fuel gauge now always shows dead empty when I know I have
a full tank. When I turn my headlight switch on, I have no instrument
cluster lights except the turn signal/emergency signal indicators,
which just stay on. The high beam indicator works, but only when the
headlight hi-beams are actually OFF. The speedometer doesn’t work, the
factory clock stops, the temp gauge is dead. However, in daytime
driving, those 3 items work, though the fuel gauge stays dead all the
time.

I’m not a D-I-Y’er, so a friend of mine who is experienced in
installing aftermarket sound systems did it for me. He’s at a dead end
at trying to troubleshoot this problem, even with my Bentley manual.
ANY suggestions, advice, guidance, etc., are encouraged and welcome.

THANK YOU!