Remove all flatware, dishes and racks. The arms of the Bosch dishwasher may not spin because dishes are positioned in a way that impedes movement. Another possibility is that flatware has become lodged in the bottom of the unit.
Inspect each of the spray bars. If mineral deposits or sticky food residue is evident, clean the holes with distilled white vinegar and an old toothbrush. Clean the entire dishwasher by placing a large bowl that's turned upward on the bottom rack. Place two cups of the vinegar in the bowl. Do not add any other liquid, detergent or soiled dishes to the load. Run the dishwasher through a regular cycle. The inside of your dishwasher will be fresh and clean. The spray arms should spin freely.
If the spray arms turn freely but are not receiving enough water, it is indicative of a restriction in the pump. If the pump is malfunctioning, it needs to be replaced. A replacement kit can be purchased online from appliance repair sites that specialize in Bosch replacement parts. It can also be purchased from your local Bosch appliance service center.
Older models of Bosch dishwashers may present fire hazards. Bosch Home Appliances and the United States Consumer Product Safety Commission have announced a voluntary recall of models manufactured between May 1999 and July 2005. Consumers are advised to stop using the recalled models immediately. Contact your Bosch appliance dealer for complete details. You will need the model number of your dishwasher.