I've been thinking about this and the solution may be easy. If you are using the console keyboard us, the grave accent should work and the "2" should shift to "@". Enter
loadkeys us-acentos
Now the grave key should seem to do nothing unless you press space afterwards, and "`a" should generate "à". If this is OK, then the problem is simply that the OS is using the wrong keyboard. If you still get "`a" instead of "à", then us-acentos is not being loaded: it must have a bug in it.

If the problem is that you can't find how to switch to us-acentos permanently, and you don't want to keep typing loadkeys, then rename the driver. Delete us.map.gz and rename us-acentos.map.gz to replace it.

If the problem is that us-acentos is not loaded because it is faulty, there's no obvious solution — except to use a terminal emulator instead of the console!

Hi:

I did 'loadkeys .../us-acentos.map', as you told me and now I have accents in the console. Thanks a lot.

"If this is OK, then the problem is simply that the OS is using the wrong keyboard". Why is that? My physical keyboard is a US keyboard. Regards.

I should have written "keyboard driver" rather than "keyboard".