Rear door won't open unless I disconnect battery

I have similar issue on 03 4runner. The rear door will not open unless I disconnect the battery or unplug the module and then reconnect, but it will then open only once. I replaced the module (used) today and it made no difference at all. Am I missing something, or did I purchase a loser? Is there a trick to somehow recycle/reset the module so it will function properly more than just one time? My son returns to school in a couple days and I hate to install a battery disconnect switch under the hood just to get one shot at opening the door...

Thanks for any suggestions.
K in Marietta, GA (new to this forum)