---
title: How do I diagnose and repair HVIL fault code 36.4 (Vehicle High Voltage Interlock Loop broken) on a Battle Motors BEV?
description: Battle BEV won't go EV-Ready with a 36.4 HVIL fault? Find and fix the open interlock loop with a meter and the prints — no scan tool needed.
---
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# How do I diagnose and repair HVIL fault code 36.4 (Vehicle High Voltage Interlock Loop broken) on a Battle Motors BEV?
## Step-by-step dealer procedure for FC 36.4 HVIL Broken on Battle Raider and Raider N BEV trucks (PM250 and IM425). Covers two paths — fault out of nowhere and fault after a repair — using only a multimeter, the dash, and the prints. Includes the full HVIL loop map, the power-sled split test, the required new-PDU/cable check, connector part numbers, and when to open a support ticket.
\# FC 36.4 — Vehicle High Voltage Interlock Loop (HVIL) Broken
\*\*Dealer diagnostic procedure | Battle BEV Raider / Raider N | PM250 and IM425 | Rev A, September 29, 2026\*\*
\*\*Read the complete 22-page FC 36.4 HVIL Diagnostic Procedure before testing.\*\* It contains the connector photographs, schematics, diagnostic record, both diagnostic paths, measurements, warnings, verification, and support-ticket requirements.
[Open the complete FC 36.4 HVIL Diagnostic Procedure (PDF, 22 pages)](https://app.hubspot.com/api/filemanager/api/v2/files/223160969399/signed-url-redirect?portalId=22125820)
\## Stop here first
1\. Record every fault displayed on the dash, not just 36.4. A simultaneous component communication fault may direct you to that component’s connector first.
2\. Determine whether the fault appeared after HV, battery, charger, ePTO, heater, chiller, charge-port, PDU, VCU, harness, frame, or body work. If yes, use \*\*Path B: After a Repair\*\* in the PDF. If no, use \*\*Path A: Out of Nowhere\*\*.
3\. If the cause is not found within \*\*2 hours of diagnosis\*\*, stop and open a support ticket with the \*\*Section 8 diagnostic record\*\* completed. Record actual measurements, not “OK.”
\*\*High-voltage warning:\*\* The HVIL circuit runs through high-voltage connectors. Do not unplug, reseat, or flex an orange HV connector or cable until HV shutdown and zero voltage have been verified as specified in Section 7 of the PDF and the BEV Powertrain Service Manual. Never bypass an HVIL point to run the truck. The only permitted jumper plug is the specified \*\*A18 ePTO jumper plug\*\*.
The PDF is the complete procedure. Use its connector identification, motor-specific differences, diagrams, test instructions, and documented pass/fail guidance rather than this overview alone.
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