Bad daytime running lights wiring?

I live in Canada and a few months ago I purchased a used 2011 Prius III from a Dodge dealer in Arizona. Part of the Canadian RIV import requirements was to have daytime running lights installed in the car. I figured since I'd have Canadian Tire do it because they're also the ones doing the provincial and federal inspections. So they installed a module something like this: Daytime Running Light System | Canadian Tire

Even though they did a very poor job at the actual installation (the unit was not secured, held in place by taught wires - ugh) it seemed to work.

However, since then I have noticed every so often while the car is sitting in my garage, the headlights will be on! This is with the car fully turned off, keys removed. If I wait long enough the lights will finally turn off on their own - but it can take a while. I'm afraid that they've hooked the sensor wire from the DRL module to a wrong circuit - it's detecting when some other circuit is energized even when the ignition is off. Another clue that led me to this conclusion is that when it's happening, I can hear a very quiet electric-motor-like sound coming from the rear of the car. I'm not sure what it is, but perhaps battery related?

Anyhow - I'd like to get your expert thoughts on this - does anyone know what sort of functions happen to the Prius when it is sitting completely off and idle in a garage? What could be causing the electric motor sounds from the rear? And if I take the car back in to Canadian Tire to get them to fix the DRL module wiring, is there any recommendations I can pass on to their "mechanics" to inform them of the proper circuit to use?

Thanks!

 

Oops, I just realized I posted this in the Gen II forum - can a moderator move this over to the Gen III forum?