Specifically, th VO;lvo relyas seem to have a penchant for cracked
solder joints inside of them. Remove the relay, then open the case.
Resolder each of the solder joints even if they look OK. If you don't
know how to solder, find a fried who does. It isn't difficult. See:
http://w6rec.com/duane/bmw/solder/

Generally, the contact points in a relay are plated. Once they get to
the point of needing to be sanded, they need to be replaced. What
happens is this- the contact points should be fairly flat with a large
contact area. Often they are nt. The electricity arcs between them,
and usually that's OK, but eventually the arcing canwear through the
plating, or foreign matter gets between them and becomes carbonized.
This can weld to the surface, or cause arcing on a very small ppint
that wears through the surfact of the opposite contact. Whatever the
case, the surface becomes pitted and the plating is lost. Once this
happens, sanding and burnishing can give the relay a bit more life,
but in all but the most benign cases, teh relay will eventuially fail
again, and at greater frequency the more it is done.

If the contact area looks ugly, try this- take a dollar bill and cut a
strip about 3/8" wide off one edge. wet it with WD40 and then rub in
some flour of pumice. it is a very fine abrasive. Then place this
between teh contacts and pull it through. Repeat until the contacts
are smooth and shiny. Clean the contacts up with alcohol to remove all
traces of the WD40 and pumice. But ifyou do this it would be best to
have a spare relay on order. You will probably need it- sooner or
later.

Bottom line- relays are a way for a small switch that can handle only
small electrical loads to turn on and off something that takes a high
current load. A relay does this mechanically with an electromagnet. A
better solution is a solid-state relay which can have a life span of
ten-fold or more over a mechanical relay. Hmm... I have a 10 amphere
one sitting right in front of me... Hmmm.... Off to look at the wiring
diagram!  ;-)

            __  __
    Randy & \ \/ /alerie's
             \__/olvos
'90 245 Estate  -  '93 965 Estate
  "Shelby"     &      "Kate"