Tools needed: # 2 Phillips and flat blade screwdrivers
1. Disconnect & pull out dishwasher.
2. Unplug power supply cord from rear of power module.
3. Lift off tank fleece insulation from right side of dishwasher.
4. Lift off cover from power module
5. Two plastic base tabs hold the power module in place. To remove power module, gently pry base tabs until they clear module and lift the module up from the base. If necessary, gently pry up the rear of the power module.
6. Disconnect top / side wire harnesses from power module, making sure to remove the harnesses with their caps, not individually.
Not all terminals are used. To protect power modules, two plugs are used to cover unused terminals.
TIP: Check error codes before replacing power modules. Many good power modules are replaced and faulty parts aren’t replaced, causing repeat calls.
CAUTION – 80% of all controls returned for analysis check out OK. Most control issues are due to loose connections and error codes for other parts.
And here's the service manual for the Bosch Ascenta dishwasher: Bosch Ascenta Dishwasher Service Manual, 2nd Edition
Source: Bosch SHE6AP06UC/06 dishwasher