cell phone booster

A customer came to me recently with a small electrical problem. He had his old school cell phone booster pack installed in his 2008 Avalanche and his battery kept going dead. I checked it and the shop that installed it wired both the +12V and Ignition to constant 12V. I rewired it so that the constant went to constant and the ignition went to the ignition. Now after about a week, he will be driving and the battery will start discharging while the vehicle is running. I reversed the wire and it still does the same thing only now when you turn it to accesssory, the vehicle tries to start. Any help would be greatly appreciated.

Just wire it to ignition... No constantUNLABELED Custom Car Club President