Going to go check out a 2005 Prius

All the checks you listed are fine. A few additions to the list:

1. If the car has HID headlights, turn them on at the beginning of your test drive. At the end, make sure the lights are still on (intermittent lights is a known problem area with newer 2G Prius - but should not be a problem with the 2005 model year.) Also, if the car has HID, refrain from turning the lights on and off repeatedly as that does not help the longevity of the lights.

2. Make sure the MFD (multifunction display) in the center of the instrument panel is working. This is another known problem area, due to a loose solder joint that may develop over time.

3. While looking in the hatch for water leaks, check the spare tire well and the area where the 12V battery is located (right rear corner of hatch floor.)

4. Make sure that no warning lights appear on the dashboard.

5. Prius makes all kinds of unusual noises. For example, the inverter emits a high-pitched whine when the car is decelerating. If you repeatedly pump the brake pedal when the car is READY, you'll hear the brake pressure accumulator pump run. When you first start the car and when you turn off the car, you may hear the coolant heat recovery pump run for a few seconds. This pump moves hot engine coolant between the coolant reservoir and the engine. The purpose of this is to speed up engine warmup time, hence reducing exhaust emissions during the warmup period.

6. The car has an electric AC compressor, so when the compressor comes on that puts a load on the traction battery and the inverter. Therefore I would not expect you to notice any change to engine idle speed (if the engine is even running, and it probably will not be running once the engine is warmed up and the car is stopped - except when the traction battery SOC gauge drops to two red bars.)

7. Will the car come with any warranty, such as 90 days, 3K miles on the powertrain? If it does not, then I suggest you negotiate price and terms with the salesrep, subject to vehicle inspection by Servco Pacific. If any issues are found, the Ford dealership should either agree to pay for the repair, or allow you to cancel the deal without penalty.

 

That's a BIG red flag! I'd pass on this one.