Electrical one offs - radios, alternators, switches

[Joseph Yakubik <75363.2524@compuserve.com>]

A while back I asked about the voltage regulators for the Bosch alternators due
to my battery dying regularly and got a few replies ranging from: "Yep, it's
busted" to "Yeah, mine too." or "Check your current flow".  

After it died again I took the least painful course and checked current draw:
Pegged at 250mA+ (sorry, low tech analog multimeter).  A little plug and play
with the fuses:  my radio draws lots of current when "off".  A  little playing
with the switches and I determined it only draws this current in its "standby
mode".  It can sit in "standby" for up to three hours after ignition off.  A few
days of this with short, high electric usage trips (heaters, defog, blower, etc)
can kill a battery I guess.  BTW aftermarket Blaupunkt radio.  Factory Audis
(Gammas w/ traffic warning excepted, maybe) don't have a "standby" mode.

I did do a (very) little research though into the "electronic voltage
regulator".  Hella makes replacement "on-board" replacement electronic
regulators for Bosch alternators.  (pages 109-113, 94/95 catalog.  Apps from
Audis to John Deere, complete with Engineerd (sic) perfection).  I don't know
how these compare to the "off-board" Motorola modules a la EC; but if very
similar, I'd rather keep the cable traipsing to a minimum.  I've got high
ignition-off current draw, but I might have a bad regulator, too, jury's not in
yet.

In reference to someone's dealer "We can't make the factory switch light up":
BS!  All factory switches can be made to illuminate in almost any fashion.  All
the time (seat heaters, ABS, warning) or headlights only or variable.... a
little cut-n-splice is involved though.

Radio installs:  Older VW/Audis did not run an ignition switched wire to the
harness.  This does not mean you can't do it later.  Again, you want ignition
off = radio off, wire it that way, almost all aftermarket radios support it but
the factory's probably don't (still checking on that one, I'm suspicious) if
you don't, then wire it another way -- watch out for the power antenna/amp
signal though.  Some radios may be looking for an ignition on signal.  The
factory radios have two "power on" switched outputs:  one (typically) unused,
the other doubled up amp and radio antenna.  If you're a tape or CD guy a "power
on, but antenna down switch" is possible.

Brake pad wear warning circuit  ( yellow circles):  this looks for continuity.
If the previous owner/driver drove all the way to where the wire was sheared
through it will stay on regardless of pad thickness.  If the owner balked at the
high replacement cost of a wire cased in plastic ($30 +)  he might have left it
hanging, warning blazing away.  The wire doesn't have to be sheared, but only
come into contact with ground (rotor).  To disable the warning you could short
the system at the plug, or to "fix" it, solder the wire, or replace the sensors.
BTW '91 200's have this up front only, no rear sensors.

Joe Yakubik
back from computer Purgatory