Okay, to expand on Maxi's flooding suggestion. Get some very HIGH value treats, NOT the regular stuff. Put these in a baggie or in your pocket. Put your dog on a leash tethered to your wheelchair, or to a non-moveable object (like the fridge) and sit your wheelchair next to that. Now get the dog's attention & give it a treat. Praise the dog. Have it sit.
Turn in the chair and hold out a treat to the dog as you turn the chair ON.
Make sure you work out the TIMING (I suggest you say the dog's name) and turn on the chair AS YOU offer the treat - so the dog begins to CONNECT the SOUND OF YOUR CHAIR => with the TREAT. repeat, repeat. (chair off, ON =>TREAT!)
If that does not work (as I've tried to explain) read up on CLICKER training & start with that, and then phase into the sound of the chair being turned on, as something you want the dog to *KEY ON* for a reward.