I bought a new headlight assembly for a ford focus 1999 and thought I'd save money and do it myself, I was able to take out the old assembly and when I was going to put the new one in I noticed three sets of wire's, I know two are for the bulbs but what is the third set for? On the old assembly they are connected to a small black box but I can't get this out and it doesn't come with the new one
I've search over all our resources and have not found any information about a electrical connection on the back side of the headlight. I think you may have gotten a wrong part. You may have gotten a headlight with out the option you old headlight has. So double check with the person you got your headlight from. Call some other suppliers that has your headlight assembly to check with them also.