You do not need to revoke the FEIE election just because your earnings in a given year are U.S.-sourced; the exclusion simply wouldn't apply to any of your earnings in that year. Once you choose to exclude your foreign earned income, however, that choice remains in effect for that year and all later years unless you revoke it.
As long as the election remains in place, however, you cannot take the additional child tax credit or the earned income credit.
From the IRS Tax Guide for U.S. Citizens and Resident Aliens Abroad:
Effect of Choosing the Exclusion
Once you choose to exclude your foreign earned income, that choice remains in effect for that year and all later years unless you revoke it.
Foreign tax credit or deduction. Once you choose to exclude foreign earned income, you can’t take a foreign tax credit or deduction for taxes on income you can exclude. If you do take a credit or deduction for any of those taxes in a later year, your election for the foreign earned income exclusion will be revoked begin-ning with that year. See Pub. 514 for more infor-mation.
Additional child tax credit. You can’t take the additional child tax credit if you claim the foreign earned income exclusion.
Earned income credit. If you claim the foreign earned income exclusion, you don’t qualify for the earned income credit for the year
