85 4KSQ - dash lights problem

[Rory]

Searching through the forums for solutions to electrical problems can go on
forever ;-)

My 85 4000 S Quattro has an electrical problem with a few of the dash lights.

All of the outside lights work properly.

When I start the car the turn signal indicator in the dash starts to flash, but
the exterior turn signals do not come on.  When voltage increases to 13+ volts,
the turn signal indicator stops flashing and the alternator and emergency brake
warning lights illuminate.  When the turn signals are activated, the alternator
and brake light flash at the same rate as the turn signals, but alternating
between the two.

Generally speaking, when I accelerate the turn signal indicator and the oil
warning lights flash in unison, alternating with the emergency brake warning
light.  The rate at which they flash is the same as when I activate the turn
signals.  While this is happening the alternator warning light remains illuminated.

The car has had an after market stereo installed which has a lot of engine
noise.  This usually indicates a bad ground to the stereo, and based on what I
have read this seems like a possible culprit.  I read something about corroded
tail light assemblies needing to be cleaned, the need to individually ground
tail lights, sender issues, and someone suggested the voltage stabilizer for the
dash could be blown.

If anyone has a suggestion on where to start, I would really appreciate the help.

Thanks again,
Rory

SF, CA
'85 4000 S Quattro
'89 CRXsi
'76 914

PS My Bentley manual is on the way =)