mercedes E300TD 210 A/C problem

[MoVAC]

hi, mercedes E300TD, 99, auto. ac problem ,ac opperates , pressures good, runs for about 4 minutes then cuts off as if normal cycle, but it doesn't come back on again. if ignition is switch off for 5-6 seconds and engine started again, the ac comes back on, but only for another 3-4 minutes, and so on. changed pressure switch but no change. problem code shows eb1 416 which i find is "engine coolant pump motor" does this ring any bells with anyone? thanks MoVAC