WARNING: This page is about a different car, the 2017 RAM ProMaster 3500, 2017 RAM ProMaster 2500, and 2017 RAM ProMaster 1500. However, it is still accessible from the selected car via links, so may be relevant.
Courtesy of CHRYSLER GROUP, LLC
The Glow Plug Module (1) is located behind the air cleaner body and in front of the Powertrain Control Module (PCM).