where is impeller located on my Bosch classixx dishwasher?

You have to remove the left hand panel and the underside panel.
It does not have access to the impeller from the inside of the dishwasher. It is on the underside
The pump is easy to identify as it has the grey truncated drain hose fixed to it.
It has a white twist off top half which is quite tricky to remove and is on very tight.
You can use a screwdriver to lever the retaining part out of the way and simultaneously twist it undone.
You will see which way it rotates by the slots in the top of it.

In the sump on the left is a cover thats held on by a screw. Remove this and you will see the impeller for the pump. Make sure nothings jammed in there. The impeller should just ping round in stages.

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You can sometimes inspect the impeller of the drain pump from inside the machine .

Just take out all the filters and use a cup, bucket and cloth to remove the water.

At the very lowest point on the left you may see a single Torx screw. It holds a simple plastic cover over the impeller.

The impeller should rotate freely with a bit of magnetic resistance.

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For more troubleshooting of Bosch dishwasher:---

The Bosch Classixx Dishwasher Is Not Draining

Bosch, a German company, produces consumer appliances that are sold around the world. It produced the Classixx series, which is an older series of dishwashers only sold in the United Kingdom. A common problem with these dishwashers is that they sometimes don't drain properly. You can often easily fix this problem, saving yourself money on service fees.

1. Pump/Water Level Control

   • The dishwasher pump is responsible for moving water out of the tub. The pump can get clogged with debris, which you can clean out with a toothpick. Remove the bottom rack and spray arm to access the pump. If the pump looks clean, see if any component is broken. The impeller inside the pump often breaks. You usually cannot fix this component, which means that you must replace the whole assembly. Check the water level assembly, which is located under a metal panel on the left side of the dishwasher. Clean the assembly if dirty.

   Hoses

   • Your Bosch Classixx dishwasher often won't drain due to a kink in the drain line. Straighten the line, or replace it if it's badly crushed. Disconnect the dishwasher from the power supply, and remove the drain line. Look inside it with a flashlight, and dig out any clogs with a plastic spoon. If you have an air gap installed, clean it out. The air gap is located near the sink. If you don't have an air gap, install a high drain loop. Attach the drain line to the base of the countertop and create a loop. This prevents water from the sink from flowing into the tub.

   Check Valve/Household Plumbing

   • The check valve is responsible for preventing water exiting the dishwasher from moving back into the tub. The valve is located near the pump assembly. Examine the valve, and see if anything is preventing it from opening and closing. Clean it out. If the valve is stuck open or closed, order a new one from a Bosch authorized parts dealer. Verify that your household plumbing is draining properly. If not, clean it out with plumbing tools or cleaning products.

   Motor

   • If you haven't used your Bosch Classixx dishwasher in a while, disconnect the dishwasher from power source, and check the motor. Oftentimes, the motor sticks if you haven't used it for a while. Turn the motor until it freely rotates. If it won't turn, you must order a new motor from a Bosch parts dealer since this component is difficult to fix.

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     You can see the impeller on left at bottom under filter tray and cover plate, it moves but does not spin, will return to original position if you twist it.

     The left hand side is the drain pump, and it should act the way you describe it. Just look at the right hand, lift up the plastic cover and you 'll find another hole, this is the wash pump, try to turn it, probably blocked by an obstacle or the seal is stuck. Pump motor is rarely defective.