I have several 300W and 600W landscape lighting transformers. These were shipped with an ordinary Intermatic plug-in timer behind a door in the housing, with a cord from the interior of the housing which plugged into the timer. It was simple to unplug the timer and replace it with an AM486 appliance module. The socket on the Intermatic is on its side and I had to undo the wire clamp and pull another 2-3 inches of wire through to reach around to the socket on the bottom of the AM486.
These have worked fine for more than 10 years, however winter temperatures here are rarely below about 20 F. The housing shields the appliance module from rain but is open on the bottom so it gets filled with spider webs.