That's a great list, Bob.
To elaborate on the underdash stuff: The instruments are all grounded via a
couple of daisy-chain wires that have ring lugs to go over one of the
mounting studs on each instrument. If the daisy-chain wires aren't connected
to the chassis, or if an instrument has been removed and then replaced
without the daisy chain wire being replaced, then strange things will
happen... Mostly to the dash lighting, but also to the tach. I've tested and
confirmed that the tach will work with the daisy-chain wire missing....
Provided you've got the panel light, with a good bulb, installed. The return
current flows to the tach case, through the light bulb filament (not enough
current to cause it to glow), then through the other light bulb filaments
for the other instruments, to ground. Of course, as soon as you turn on the
panel lights, it puts the tach case at 12 volts, and the tach will quit
working.
If your temperature and fuel gauges both appear to read incorrectly, first
check the output of the "instrument voltage stabilizer". This should be 10
volts on your DC voltmeter. If it's ungrounded (eg. mounted onto the back of
the wooden dash panel as mine was), then it will put out 12 volts and cause
the gauges to read high. If it's burned out, then it will put out zero volts
and your gauges will not read at all. Mechanical replacements (the OEM part
is a bimetallic strip with contacts at one end and a resistance wire wrapped
around it) are available from Rick or Curt, and electronic replacements are
occasionally available on eBay and soon through ...uhhh... other channels.
;)
Best regards,
Theo
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