An experimental study of the photofragmentation of Ar-3(+) at wavelengths > 650 nm has been undertaken in order to investigate the reaction channel Ar-3(+)+h nu --> Ar-2(+)+Ar. As a function of photon energy, measurements have been made of the Ar+/Ar-2(+) branching ratio and the relative kinetic energy of the photofragments. A steady decline observed for the latter as a function of decreasing photon energy, suggests that the dimer ions emerges from the photodissociation processes with a very high level of internal excitation. Supporting semiclassical calculations of the decay dynamics confirm the trend seen for the Ar+/Ar-2(+) branching ratio, but do not reproduce the quantitative details. The calculations do, however, provide strong support for an experimental analysis of the energetics of fragmentation, and show that Ar-2(+) can appear either in the electronic ground state, but with a very high degree of vibrational excitation, or in the weakly bound (2)Pi(g) electronic excited state.