Date:         Mon, 19 May 2003 13:13:21 -0400
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: horn problems
Comments: To: Tonya Pope <Tonya@HOLOREALITY.COM>
In-Reply-To:  <200305190700632.SM01548@tonya>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 09:58 AM 5/19/2003, Tonya Pope wrote:
>attached to a dangling horn mechanism, they get close to 12V
>(probably a matter of me not attaching the leads as good on the
>meter) and sounds like a sick duck, but works.  When I put it in
>place and tighten the nut holding it on, I only get about 6V across
>and all you hear is a thunk.

The thunk is the noise of the diaphragm being moved, but not enough to
break the internal contact...

Use your meter and find out where the other 6v is being dropped -- you've
got a poor connection somewhere.  The wiring is very marginal anyway,
you'll get improvement by using the horn switch to drive a relay instead of
the horn directly; but this isn't marginal, it's broken.  Use B+ and B- (at
the battery) as your reference points for measuring and follow the voltages
around.  Ideally you'd get no drop at all until you get to the horn, then
the entire voltage dropped across the horn -- in practice you'd expect to
lose possibly as much as a volt in the wires.

Because the horn is a rapidly interrupted load it will generate lots of
noise on the wiring (not to mention your ears) when it's working -- if this
makes it hard to measure substitute a static load for the horn: old
headlight would be ideal, but one or two stop-light bulbs in parallel
should give enough load to get useful voltage drops.

Come to think, your problem is bad enough that wherever the bad connection
is will probably get pretty hot if you use any serious load and operate it
for more than a second or two -- better to use say a single tail-light (not
stop-light) bulb and see if that gives you enough load to follow the drops
around.  Otherwise the smoke may locate the problem before the meter does.

david

--
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"