We have studied the production of ArN+ starting from the two symmetric charge-state reactants Ar+ + N-2 and N-2(+) + Ar. For both reactions we measured the total cross sections as a function of the relative energy, in the energy range from 5 to 45 eV. Estimates of the reaction thresholds and symmetry considerations suggest that the reaction Ar+ + N-2 produces ArN+ essentially in its first excited state A (3)Pi, while the reaction N-2(+) + Ar produces ground state ArN+ ions. This fact explains the discrepancies between different estimates of the dissociation energy of ArN+ obtained in previous studies.