Does the ox have a name? Why are you spraying it? Flies?

Seriously - what year and model?

If you spray a de-oxidizing spray in to the fuse box and it works, then you've gone a long way to isolating the problem. But, unless you're very precise with the spray, you're probably getting other fuses, too. It may be that there's a different fuse that is upstream of the wipers. When the spray hits that fuse, it may make the connection.

The noise might be a relay, but without more info it's tough to say.

Recommendation: remove and inspect all the fuses, or at least the ones that are near the spray pattern. Check the fuse holders for corrosion or heat damage and warping.