Igather that by PCBs you don't meanPolychlorinated Biphenyls
<http://www.epa.gov/pcb/>

On 2/6/2013 1:00 PM, David Beierl wrote:
> At 03:12 PM 2/6/2013, neil n wrote:
>> Thanks Dick and David.
>>
>> Thanks *very* much for insights into what may have happened. Yes,
>> maybe that solder joint was re heated. The insulated female terminal
>> from 30 to relay shows what may be a slight small burn mark.
>
> Well it certainly got hot enough to melt the solder around the
> terminal, but that was from high resistance and arcing once the joint
> had already gone bad.  The flux residue around the solder pad also
> suggests that it may have been reworked/reflowed -- i.e. repaired --
> previously, which is what Dick was talking about.  That would have
> been done on the bench and not affected the female terminal.
>
>
>> The replacement 109 relay is a different design; the pins go directly
>> to the internal parts. Which begs a question:
>>
>> How do I know which way the relay box goes back on the relay base?
>
> VW relays with PCBs have a pair of molded-in rails inside the cover,
> that the board slides into to support it against overall
> distortion/vibration.  Failing to mount the cover in this orientation
> will contribute to terminal failures.
>
>
>> Since this was my first time at a swap (or work of this magnitude), I
>> went with OEM wherever possible. I assumed the 109 relay had some more
>> complex electrical "voodoo" going on so I made a point of using that
>> part. Same with fuel pump relay. The ABA fuel pump relay has large
>> 30-87 terminals and a small 85 terminal (ECU) so a generic relay block
>> was of no use. The 109 also has the small 85 pin. IIRC, I had been
>> using a relay socket for the 109 along with a separate wire to 85 pin.
>> Yes. Seems so. Image:
>>
>> https://sites.google.com/site/tubaneil2/PowerRelayDiagram.jpg I
>> don't recall when or why I deleted this socket.
>
> This relay according to the diagram on the side has an additional
> component (likely a diode?) wired in parallel with the activating
> coil.  This would likely be to protect the electronics driving the
> relay from being fried by the voltage pulse when the coil is
> de-energised.  You'll want to know what that component is before
> replacing it with a generic relay (which you otherwise could by
> taking a standard relay and connecting the 86 terminal to the 30
> terminal.  This particular relay is operated by switching the ground
> lead rather than the hot lead of the coil.  All this suggests to me
> that it's being driven by an ECU output, is this correct?
>
>> type. They will fit a FLAPS type generic relay socket. Both the Jetta
>> Power Supply and Fuel Pump relays have a suppression component
>> (appears to be a resistor) in parallel on  85 and 86 so I would make
>> sure a substitute relay has same.
>
> Ok, how specifically does it appear to be a resistor?  What does it
> look like, exactly?  Any numbers, banded end, color bands, body
> material, body color, body shape?  I guess a parallel resistor could
> be used to mitigate a voltage spike, I'm just not accustomed to the idea.
>
> Yrs,
> d
>