2005 Mercury Grand Marquis Light control module

My battery want stay charged in my Mercury. I want to know do you think the light control module could cause it to drain

Yes. I had this happen on a 2000 Lincoln.

The customer complained that the battery would drain down as the vehicle sat idle. The vehicle was in the shop after hours so the lights were off in the shop. I went into the shop to something at the bench, and as I was working at the bench the shop lit up slightly. I turned around and the interior lights were on in the Lincoln. After about thirty seconds the lights turned off. So I sat there and watched the car. The interior lights would come on and turn off. The timing of this was random.

Unplugging the light control module stopped this from occuring.

Tester

You might also have someone perform a parasitic draw test