I believe, on the KDI-19, the bi-metals are in series with the wash motor. Therefore, if the motor isn't drawing enough current due to low water fill, plugged pump screens or broken/stripped wash impeller, the bi-metal won't flex enough to allow the soap cups to release. Also, dishes won't be clean & soap won't be washed out of the soap cups. Check to make sure it's getting sufficient water, that the round screen below the washarm is really clean & that the wash impeller is not broken or stripped. Also, check the center post on the washarm support. make sure it hasn't come loose from the bakelite housing.