Date: Sun, 17 Jun 2007 00:43:03 -0500
Reply-To: Matt Roberds <mattroberds@COX.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Matt Roberds <mattroberds@COX.NET>
Subject: Re: Catastrophic failure of coolant level sensor
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
> From: Steven Smith <kewsps@YAHOO.COM>
> Date: Fri, 15 Jun 2007 12:17:15 -0700
>
> I tried tightening the nut in the center of the temp Guage and it
> stopped blinking. Turned it a little more and it started again. So I
> pulled the instrument cluster and removed the center nut (ground i
> believe) and saw that the copper ring under the nut was broken off
> right where the line goes into the plastic ribbon.
It is possible to "patch" circuit boards with thin pieces of solid wire.
You CANNOT use a big soldering "gun" (over about 50 W) to do this -
it'll make things worse. What you want is a "pencil" in the 20 W to
40 W range. You also need rosin-core (electronics) solder - acid-core
(plumbing) solder will appear to work, but the acid will eventually eat
the connection.
The basic procedure is to scrape off any coating (often green) over the
copper traces to expose shiny copper, solder a longish piece of wire to
one side of the break, then trim the wire to length and solder the other
side. Alternatively, you can follow the trace to where something else
is soldered to it, and attach your new wire to the same solder joint.
If you end up with a long length of wire, it's a good idea to use some
epoxy or clear RTV or similar to glue the wire to the circuit board at a
couple of intermediate points.
You can also use this trick if you have a damaged pin in a multi-pin
connector that attaches to a circuit board - solder a piece of wire to
the circuit board (electrical connection), glue or zip-tie the wire to
the board (mechanical connection), then put something like a 1/4" push-on
connector on the other end of that wire. Cut the harness wire a few
inches back from the multi-pin connector, put a mating push-on connector
on the harness wire, and plug it together.
In your particular case, you might be able to solder one end down
and then coil the other end in a loop under where the nut goes to make
contact.
If you want to practice, just about every piece of electronics around
has a circuit board in it. You can even practice on scrap/junk
electronics - just check with an ohm-meter when you're done that you
made a good connection. If you'd rather have someone else do it, a TV
repair shop (if you have any left in your town) can probably do it for
their minimum labor charge. Or, find a local company that does
electronics assembly, and offer lunch to one of the little old ladies
that solders things for fixing your instrument cluster. :)
Matt Roberds
