We study a simple deterministic map that leads a fully connected network to the Heider balance. The map is realized by an algorithm that updates all links synchronously in a way depending on the state of the entire network. We observe that the probability of reaching a balanced state increases with the system size N. Jammed states become less frequent for larger N. The algorithm generates also limit cycles, mostly of length 2, but also of length 3, 4, 6, 12, or 14. We give a simple argument to estimate the mean size of basins of attraction of balanced states, and we discuss the symmetries of the system including the automorphism group as well as gauge invariance of triad configurations. We argue that both symmetries play an essential role in the occurrence of cycles observed in the synchronous dynamics realized by the algorithm.