I have lost my companions in the Hoover Dam. They are somehow off the map and I can't find them even by turning off the clipping. They aren't where their map markers show them. Is there a cheat code or something that will bring them to me ? Backing out of the game and reloading doesn't do it, nor does fast travelling to another map point.

If you're playing the PC version, open the console and type this:
prid (character's reference ID here, which you can find on the Fallout Wiki)
moveto player

Thanks so much. I'll try it.

it didn't work. i get message about script not compiled and endline expected. is there something i need to add after moveto ? I tried "player" and my char ref code but neither worked.

Wait couple or 7 hours. If didn't work, there is noting can do.

Sorry, I should have been more specific. For example, if you lost Raul, you would type HIS reference ID. It would look like this:
prid 000e6105
moveto player
You have to hit 'enter' after typing the reference ID and proceed to type 'moveto player' on the next line. That should work unless it's the invisible companion bug. I lost ED-E to that bug and it was carrying a ton of my weapons.

thanks again, i'll try that and let you know.

That worked ! I am most appreciative. But the quest still won't update. The major told me to talk to Ranger Grant about protecting the president, but he just says there's a lot to do and says goodbye. Any ideas how to make it progress ?

Open the console, click on him and type 'disable'. After he disappears type 'enable' and that should allow you to initiate dialogue with him to start the quest.

thanks again, I'll try that tomorrow.

that also worked. once again, thank you so much. i'm really diggin this game and I want to finish it.