[sluggo]

So if I'm reading this correctly your pump shuts off after only a few seconds? Have you check to see if you are getting continuous AC power to the pump?

Unless you have a very old system the air conditioning controller will energize the pump circuit during cooling and heating cycles, that is when the condenser and compressor are put into operation. So if your compressor is running the pump should be energized. If the condenser shuts down for any reason it will de-energize the pump.

Two or more AC units connected to one pump use a trigger relay so any one condenser can operate the pump. The trigger assembly is usually a separate small control box.

If you are comfortable working around 120VAC put a meter on the wires in the AC control box that lead out to the pump. If the wire leads to a smaller box then open that box up and meter the wires going to the pump (that is the trigger relay). If you do not show 120VAC while the compressor is on then you either have a bad trigger or a bad controller board. If you show AC power and the pump is not running then something is up with the pump (some have over-heat protection).

Another alternative is to wire the pump directly into your AC breaker panel and bypass the system controller entirely. If it runs and pumps water your pump is good and you need to look at the control circuitry.

Keep in mind that if the compressor is shutting down because of some other fault (high head pressure, etc) it will quickly shut down the system including the pump. If this happens however you should see an error code on the thermostat.

Sounds complicated but it really is pretty straight forward. Remember to exercise normal precautions working around 120 volts.

thanks!  the old pump was working fine, except it was not pumping enough water thru, so we just removed it at the slice where it leads into the rest of the boat, so I don't think it is what you mention, but I will run it up the flag pole with my tech.
As we had 2 pumps, he did go back to the shop and hard wire one of them, and it acted the same way as it did on the boat, so I don't think it is the circuity.  But always good to check.  I'll let you know.  Thanks!