There seem to be a lot of electrical issues as of late.

One thing I've found that helps is dielectric grease. You can get a small tube at any local auto parts store for under $5.

It does not conduct electricity, it stops corrosion and ensures a good contact.

Here'* my method of working on say a relay that is giving me trouble. I typically will take the possible offender off the car and visually inspect the part. If everything looks good, I have a small 12V power supply and a multimeter that I use to test that the relay is working. If it is working, I apply a light coating to each of the terminals. Then put the relay back in and remove it about 5-10 times. By doing this 5-10 times the connectors that the relay terminals make contact wtih now have a freshly scraped and protected area as well.

I do this also any time I take a new conector apart. A good connection and protective layer of dielectric grease will keep corrosion and problems away for a long time.