Industrial 12338772 Glow Plug Control Timer Switch Unit TSU

The Glow Plug Control TSU 12338772 is a vehicle-mounted timer switch unit (TSU) that automates the glow plug preheat cycle to improve cold-start reliability in military diesel equipment. It is commonly installed in AM General HMMWV M998-series vehicles equipped with Detroit Diesel 6.2L and 6.5L engines, where automatic glow plug timing and engine protection are required. The unit is an electronic timer module operating at 24 VDC, and its function is to automatically energize the glow plugs for a preset duration before and during engine cranking. Mounting is in the vehicle engine compartment, and it supports compatibility with HMMWV M998, M1025, M1038, and related military vehicles. The part number is 12338772, with alternate part number 1310055 and NSN 2920-01-175-7214. Common replacements include AM General 12460070 Glow Plug Control Box, KDS 1310055 Glow Plug Timer Switch Unit, and HMMWV Solid-State Glow Plug Controller Assembly.