Headlight Level Sensor - the saga continues...................

I have read and learned much from previous posts on this issue, and am still having trouble with this device. I have a 2005 with close to 300K miles. I bought it from a friend who lives in the Great Lakes area of Ohio, so no surprise it was going bad. He had told me that he was having intermittent issues with it, and sure enough the sensor failed. As many have noted, the headlights point straight down when this happens, so the first thing I did was read up on how to readjust them up. Later I bought a used sensor on EBay ($175.00), and inside and out it looks almost new. When I went to replace the sensor, I noticed the wiring harness it plugs into was also shot, with 2 of the three pins missing. The same people sent me a replacement for $25.00. Simple enough, splice 3 wires and away we go. I put it all together................and the MIL light still is on! I did use some bulb grease in the fittings where the harness connects together - could this be the problem? I also have not adjusted the headlights back down, as it was difficult to adjust them up in the first place. There is a tiny amount of voltage coming through one of the wires, but not through the other 2. Any suggestions folks? This does not appear to be brain surgery to replace, but it has me beat.