I have a lot to say so please bare with me. I'm troubleshooting a Frigidaire dishwasher with an inoperative circulation pump motor. I ran the water/service test diagnostic from the control panel and the water valve works and so does the heater and smaller drain pump. However when it calls for the main circ. pump nothing happens and the error code HS appears for the Hall Effect sensor (HES). I removed power connector from motor and verified 120vac at connector, but when I reconnect it to the motor it drops to 1vac. I thought maybe the motor windings were shorted or something so I removed the power connector again and my meter read 120vac again, so I connected a 100watt light bulb with leads to the connector and the voltage dropped to 1vac or less and the bulb did not light. So it seems like I'm getting voltage but not enough current at the connector. I'm thinking there's a bad circuit on the control board. Next I removed the motor and bench tested it and the HES. The motor ran fine when I applied 120vac. Then I supplied the HES w/ 5vdc and probed the output with a logic probe while I was spinning the impeller by hand and there was definitely a signal at the output. I put a meter on the output and verified it was a 5vdc pulse. I'm thinking the motor and HES is fine. I put it back in but still the same error code for the HES. Next I probe the HES connection at the control board and was still getting a signal there, so again that makes me think it's a bad control board. Please I would appreciate some more guidance before I order a new control board. How would you explain the 120vac power connector to the motor dropping to 1vac or less whenever it is connected to a load? I need some help confirming which part is bad. The onboard diagnostic said the Hall Effect Sensor is bad and to replace the motor, but in my opinion they checked out fine in the bench test. Truely Butternut

Here is a service manual which should help
http://frigidaireservicetips.com/pdfs/463_9.pdf

I will take a look at it tomorrow to see if anything comes to mind but thought you may be able to use it ASAP so am passing it along.

Fixed a buddy's TV this afternoon and had to sit down for a few beers afterward so rational thought is a little tough at the moment.

Ran the relay and triac test. Everything worked except for the main pump motor. The pump did not react at any speed, but I know the pump is good because I bench tested it earlier. This is consistant with my hunch that the control board is bad, so I bit the bullet and ordered a new one. While removing the board I noticed that the optoisolator that drives the triac was cracked, probably from a voltage surge or overheating, and that is probably what was limiting the current flow. I guess I'll know when I get the new board in a day or so.