VW Airbag Controller Problem

I am currently trying to fix my daughter’s VW Polo '00 as the airbag lamp stays
lighted. The VW dealer offers to repair it for $800.00 which is more
than the value of the car itself. The fault presented is P65535
which VW says is a failure of the control unit itself.
An OAP with a background in electronic repairs I have been analysing
the components of the PCB and can identify the function of most all
with the exception of one. It is 1 1/8" x 1/2" x 1/2" and sealed with
a twp-part epoxy at one end. That end has four pins while the other
end has two. (It looks like a little white loaf on the PCB). It has
no proper identification other than a serial number and it looks like
a two pole relay except for the fact when you shine a strong light
through it, it shines through one half of it as though there is just
space with no metal there.
If you can identify it for me it would be of great help.

I have no idea, but why not just buy a used controller online? The probability that you are going to be able to find the fault on the board yourself is pretty low, even with your experience.

Here’s a used one for $50: