NEWS | Aug. 3, 2021

Combat Vehicles: LRU Troubleshooting and NGATS/DSESTS

Some units are turning in line replaceable units (LRUs) as unserviceable when they’re actually in good working condition.
That’s not good!
Turning in serviceable LRUs drives up costs and makes units spend money unnecessarily. Not to mention that unit readiness is hurt while vehicles sit around the motor pool waiting on replacement of an LRU that was actually working just fine.
Here’s some information that will help you avoid turning in an unserviceable LRU. It’s broken down by who’s responsible for the various steps involved:
Tactical Unit Troubleshooting Responsibility
It’s important to troubleshoot LRUs exactly like it says in the TMs to prevent turning in serviceable LRUs. Be sure an LRU is tested with the Direct Support Electrical System Test Set (DSESTS) or the new Next Generation Automatic Test System (NGATS) before turning it in to your supply support activity (SSA). The NGATS or DSESTS is typically located at the brigade support battalion (BSB).

Some LRUs are turned in as unserviceable and the only thing wrong with them is they haven’t been updated with the correct software or there’s a mismatch between the LRUs software and the vehicle’s software. Planned software updates are managed by modification work orders (MWOs).
Brigade Maintenance Responsibility
The BSB NGATS/ DSESTS team has working knowledge of its supported customers’ software and vehicle configurations. When an MWO is issued, the DSESTS/NGATS team is informed. Typically, these MWO’s are performed one battalion at a time, so there are scenarios where the brigade may have more than one software/hardware configuration to update because the battalions have differing versions of software/hardware. Again, the DSESTS/NGATS team knows what each battalion requires and reacts accordingly.
When testing an LRU, the technician selects the type of LRU being tested. The next step is to select the LRU’s part number from those listed on the menu. The part number will determine the software and hardware required to repair the LRU.

Of course, the DSESTS/NGATS team must ensure it maintains its assigned DSESTS or NGATS test equipment. This means running functional self-tests (FSTs) and visually inspecting all test cables before use. It also means taking care of these cables because most of the ones used on the DSESTS will also be used on the NGATS when it’s fielded to your unit.
Tactical Unit Verification Responsibility
After the repaired or updated LRU is returned to the unit and installed, the first follow-on action is for the mechanic to verify the LRU’s software and determine its version. It must correspond to the vehicle’s software version; if it doesn’t, it will cause the LRU to operate improperly. If the software is incorrect, then the correct software is downloaded using the Software Loader Verifier (SLV) or the vehicle’s brick.

Important note: There has been a significant problem with units not ensuring compatibility between LRU’s software and the host vehicle’s software. It’s possible that a unit will get an LRU from brigade that’s just been updated with the latest software. But if that version of software isn’t compatible with the vehicle’s software, then the unit must use the SLV to download the compatible software, even if it means returning to an older version.

If you’re in a tactical unit experiencing LRU challenges beyond what’s been discussed here, reach out to the nearest combat vehicle logistics assistance representative (LAR). The DESESTS/NGATS team should also initially contact a LAR for assistance.
Or units can call the NGATS helpline at (256) 876-1470 or visit the portal page at (you'll need your CAC to access):

Contact the TACOM DSESTS/NGATS team at: