Piece of emery paper (don't use sand paper or Adjou will have kittens) so they are nice and shinney. Thin smear of petroleum jelly over the top to keep the damp out.
If that doesn't solve it, run a second heavy duty cable from battery
to fridge as a temporary measure to see what happens. The first time we used our Waeco on the yacht it wouldn't work on the higher setting and just cut out. Wiring
was to thin. Went completely over the top and re-wired with heavy duty stuff and it solved
the problem, well sort of it, it then froze me sandwiches