I back tracked everywhere I went and I couldn't find him. I checked the caves (Searchlight East Gold Mine and Fire Root Cavern) and didn't see him. I do have a bad habit of just running down a mountain side and leaving companions looking for another route down. So I went back to the mountain ridge to see if he was stuck and didn't see him anywhere. I checked all the submerge buildings down on the lake front and nothing.
Now this was all before the first DLC (Dead Money). For the longest I couldn't use Rex cause it still said I had ED-E with me. Once the DLC came out and it forced all companions to leave I was excited cause I thought ED-E would go back to Lucky 38 or Primm. Once I stared the DLC it said all companions were released and it said I lost ED-E's perk, but once I completed the DLC he WAS NOT at lucky 38 or Primm. Still nothing!
So with the latest patch I used the Companion Dismal terminal and still no ED-E at Lucky 38 or Primm.
I LOVED ED-E as a companion, especially paired with Boone, but I'm more upset at losing all the gear that I gave ED-E. I think he had at least 2 special named weapons!

I don't know what to do?
Any help or suggestions?