I'd like to share with you what we have done for 8-10 years and three motorhomes. We have a fuse switch in the 2010 CR-V that turns off fuse #32, in our case, to prevent battery drain while key is in acc position. We get power for the brake box (SMI) from the motorhome. Prior to this switch we experienced dead battery after 4-6 hours of towing. With switch installed ( no real modification to speak of) we have not experienced battery issues. Door locks and brake lights work with this setup. Hope this is helpful.