US air regulator the FAA confirmed to Reuters that the agency had approved the service bulletins and associated instructions sent to airlines related to fixing the problem.
"After gaining final approvals from the FAA, we have issued service bulletins for the affected fleet," a spokesperson told the news service.
"We are also completing the work as we prepare to resume deliveries."
FAA Administrator Steve Dickson had earlier said that the MAX fleet would need a "pretty straightforward fix."
The MAX 737 had only be approved to fly again in November 2020 after a two-year investigation following crashes in five months that killed 346 people.
Reuters reported just over a week ago that Boeing had been asked to show that numerous 737 MAX subsystems would not be affected by electrical earthing issues.
A number of airlines stopped flying the plane when made aware of the issue, which was linked to a backup power control unit in the cockpit.
The problem, which also halted delivery of new planes, was also identified in two other places on the flight deck
News of the all-clear will be a boost for several airlines that have ordered multiple MAX aircraft to upgrade their fleets.
One such carrier is Ryanair, which last December confirmed an order for 75 new MAX-8200 aircraft, increasing its total firm order to the plane model to 210 from 135 previously for a price tag of over US$22bn.
Shares in Ryanair dropped 2.7% to €16.27 on a poor day for the market overall.