[wildrage]

I know the pump itself works (tested it on the battery). I think there's either a short in the wire going to the connector, or the relay is bad. I can't test the power to the connector if I don't know the computer is sending power to it.

I was thinking - If I wired the aux pump to come on with the heater pump (run all the time), would that have any negative effect? It looks to me that the pump itself only pumps coolant from one side of the radiator to the other, so when the thermostat is closed and the car is warming up, it shouldn't affect that.

My next step is to see if I can find a short in the wire, then to replace the relay (although I can't find the 'K22' relay on any of the dealer part sites!).