From:	darling@simlab.arc.nasa.gov on behalf of Dave Darling [darling@simlab.arc.nasa.gov]
Sent:	Monday, March 29, 1999 11:01 AM
To:	Lawrence Bonkoski (work)
Cc:	914
Subject:	Re: [914] Electrical problem in my 74 2.0.

At 12:47 PM -0800 3/29/99, Lawrence Bonkoski (work) wrote:
>When I turn on my headlamps, the alternator warning light comes on at idle.
> The headlamps appear to be stock (not high-output or anything).  This
>doesnt seem to affect engine performance.

	The alternator warning light is connected to two wires.  When there
is a voltage differential between those two wires, current flows through the
bulb and the light glows.
	One of the wires connects into the "D+" wire from the alternator.  It
goes through the relay board and the main wiring harness to get to the alter-
nator light.  The other wire connects to one of the "switched power" ouputs
of the ignition switch.  When the switch is in the "on" position, it is con-
nected to the battery by way of the main wiring harness.  To get from the
light to the switch, the wire goes through one of the fuses on the fuse panel.
I think this is fuse #9.
	If there is corrosion, dirt, or other "grot" at any of the connections
on either wire, there will be a voltage drop across that wire that will vary
depending on how much current is "asked" to go through it.  The headlights use
the "switched power" as one of the "switching" lines on their relay, so that
when the headlight switch is on, there is current flowing from the switched
power circuit through the headlight relay.  This is extra current flowing
through that first circuit, which will cause more of a voltage drop across
dirty or corroded connectors.
	Clean up all of the connections.  In particular, the fuse-to-fuse-
holder connections seem to attract dirt.  Contact cleaner or "TV Tuner Cleaner"
can help.  Examine the fuse itself.  If the metal does not look reasonably
shiny, if it looks corroded, just replace the fuse.  That fixed mine--the metal
on the fuse itself was old and corroded.
	You can also check for problems with a voltmeter.  Start the car, and
put on all the stuff you can that hangs off of that circuit.  (Headlights,
brake lights [brick on pedal], turn signal, etc.)  Use the voltmeter to check
for a voltage across various connections.  The fuse is the easiest to check,
of course, because you can just touch the probes to the fuse holder on each
side of the fuse.  Testing the other connections may require you to dig into
the wiring somehow.

	Good luck!

--DD

Dave Darling                                     74 914 2.0 (VROOM!)
darling@simlab.arc.nasa.gov  <---   OR   --->     ddarling@wgss.com
     "914: The Porsche Picnic Basket.  A lid that opens on
         each end, and a handle in the middle.."  -- CHD