The Fix Weather Node Task in Polus is a long task consisting of 2 stages. The first stage of the task will vary, you will have to go to one of 6 weather nodes that are outside (Node_CA, Node_TB, Node_IRO, Node_PD, Node_GI, and Node_MLG). Once the task is started you will have to move and drag a yellow light through a maze. Starting at the top left and ending at the bottom right.
Once the first stage is completed, you have to go to the Laboratory room and switch on the weather node that you fixed in the previous stage.