Date:         Mon, 10 Jul 2000 23:33:42 -0400
Reply-To:     "Carrington, Tom" <TCarrington@ReliTech.com>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         "Carrington, Tom" <TCarrington@ReliTech.com>
Subject:      FW: Help!
Content-Type: text/plain

> -----Original Message-----
> From: David Beierl [SMTP:dbeierl@attglobal.net]
> Sent: Monday, July 10, 2000 11:25 PM
> To:   bpchristensen1@home.com
> Cc:   vanagon@gerry.vanagon.com
> Subject:      Re: Help!
>
> At 14:00 7/8/2000, bpchristensen1@home.com wrote:
> >Headlight problem; low beams work fine, but when I switch to high beams,
> the
> >high beam won't light on the driver's side, and the primary filament in
> the
> >main lamp goes out.
>
> By primary I assume you mean the low-beam filament.  It's actually
> *supposed* to go out when you put the high-beams on.   Low beam is driven
> by 56b (through fuse s21 for left side and s22 for right).  High beam is
> 56a, s10 and s9.  The dimmer switch simply switches the 56 lead from the
> light switch (which gets its power from the load reduction relay, X
> terminal on the light switch) to either of 56a or 56b.  So:
>
> 1) bad ground from that headlight assembly.  The low beam still works
> because it's grounding through the high-beam filaments, just like the guy
> ahead of you whose running light goes out every time he puts the brakes
> on.  His running light is grounding through the stop lamp filament, but
> the
> ground goes away (and neither light works) when the stop lamp is
> energized.
>
> 2) bad s10
>
> 3) bad internal panel wiring, fuse s10 to terminal c17.
>
> 4) bad 56a wire from panel to light assembly.
>
> My bet is on number one, but you can check by testing for 12v at the
> separate high-beam lamp (highs switched on, duh...).  If you have 12v
> there, it's a bad ground.  If not, start following the other stuff back
> until you find 12v.  It's not the switch, since the other side works
> ok.  If you have voltage on one end of something and not on the other end,
>
> that's the busted part.
>
>
> >I notice that in the wiring diagram that each lamp has two circuits - 56a
> >and 56b, and both sides tie together somewhere behind the dash.
>
> High and low beams.
>
> >I checked for continuity in both circuits from the dimmer switch (and the
> >dimmer switch itself) and everything seems good. One weird (?) thing I
> >noticed was that the "hot" side of the 56a circuit had continuity to
> ground.
> >Is this just due to the bulb?  (i.e. not abnormal).
>
> Hot resistance of a 65-watt headlight bulb is about one fifth of an
> ohm.  Cold resistance much less...normal.
>
>
> >Any suggestions?  All I can think of is a short in the wiring between the
> >driver's side lamp and the dimmer switch, which I imagine will be a
> >nightmare to troubleshoot.
>
> That's not it...an open maybe, but no short.  And no problem to find if
> you
> need to. :)
>
> cheers
> d
>
> David Beierl - dbeierl@attglobal.net <<- New address becomes mandatory on
> 1
> Oct, optional until then.