393.77B-HT — Heater defective or missing
FMCSA violation code under Vehicle Maintenance. 17 events recorded in roadside inspections. Severity weight: 2.
Violation Description
Heating system on commercial motor vehicle used to heat the cab or body is not operative or malfunctioning.
About This Violation Code
Code 393.77B-HT falls under the Vehicle Maintenance BASIC category in FMCSA's Safety Measurement System (SMS). It carries a severity weight of 2 (scale 1-10, higher = more severe).
When this violation is cited during a roadside inspection, it contributes to the carrier's Vehicle Maintenance BASIC score. Carriers with high BASIC percentiles may be prioritized for FMCSA interventions including warning letters, investigations, or compliance reviews.
Regulatory Reference
Federal Motor Carrier Safety Regulations
This violation references 49 CFR 393.77B in the Federal Motor Carrier Safety Regulations.
Top Enforcing States
Where 393.77B-HT is most commonly cited (last 180 days)
Click a state to see roadside inspection activity, top stations, and carrier profiles in that jurisdiction.
Citation Trend (12 months)
Monthly count of 393.77B-HT citations. Red bars mark months with OOS-triggering citations.
Most Active Stations
Inspection stations citing 393.77B-HT most often (last 180 days)
Top Carriers Cited
Ranked by frequency • 17 carriers total
Top Carriers with 393.77B-HT Violations
| # | Carrier | USDOT | # Violations |
|---|---|---|---|
| #1 | MORGAN HILL UNIFIED SCHOOL DISTRICT | 2806880 | 1 |
| #2 | IFM ENTERPRISES INC | 3227346 | 1 |
| #3 | J A M PACKING INC | 4137201 | 1 |
| #4 | VDV AUTO EXPRESS LLC | 2903150 | 1 |
| #5 | CARDENAL EXPRESS SA DE CV | 847349 | 1 |
| #6 | M&S DISTRIBUTION LLC | 3941633 | 1 |
| #7 | KUDOS TRANSPORTATION INC | 722966 | 1 |
| #8 | UNITED PARCEL SERVICE INC | 21800 | 1 |
| #9 | 3 COUNTRIES LLC | 3836336 | 1 |
| #10 | KEL&SON LOGISTICS LLC | 3976293 | 1 |
| #11 | CHILD DEVELOPMENT SCHOOLS INC | 1838818 | 1 |
| #12 | HARLOWS SCHOOL BUS SERVICE INC | 1662560 | 1 |
| #13 | ELITE TECHNOLOGIES LLC | 4429594 | 1 |
| #14 | TRANSPORTES DE MAQUILAS DE CD JUAREZ SA DE CV | 710383 | 1 |
| #15 | PASHA DISTRIBUTION SERVICES LLC | 1773940 | 1 |
| #16 | SUNDAY RIVER SKIWAY CORPORATION | 754722 | 1 |
| #17 | SVC HIGGINS ROAD TRS LLC | 4317224 | 1 |
Recent Inspections
Latest inspections where 393.77B-HT was cited • 17 total events
Recent Inspections with 393.77B-HT
| Date | Report # | State | Level | OOS |
|---|---|---|---|---|
| Dec 22, 2025 | 86647735 | FL | Level 1 | No |
| Oct 31, 2025 | 86222790 | MI | Level 1 | No |
| Oct 13, 2025 | 86039579 | US | Level 1 | No |
| Oct 1, 2025 | 86111213 | CA | Level 5 | No |
| Sep 25, 2025 | 85882979 | CA | Level 1 | No |
| Sep 10, 2025 | 85747027 | ME | Level 5 | No |
| Aug 19, 2025 | 85540783 | VA | Level 2 | No |
| May 13, 2025 | 84678305 | SD | Level 1 | No |
| Feb 19, 2025 | 84158473 | CA | Level 5 | No |
| Jan 13, 2025 | 83598947 | US | Level 1 | No |
| Dec 31, 2024 | 83512823 | WA | Level 2 | No |
| Dec 20, 2024 | 83477360 | SC | Level 1 | No |
| Nov 8, 2024 | 83140659 | CA | Level 1 | No |
| Nov 1, 2024 | 83111533 | IL | Level 5 | No |
| Oct 22, 2024 | 82985284 | WA | Level 1 | No |
| Oct 15, 2024 | 82958347 | CA | Level 5 | No |
| Feb 6, 2024 | 80844502 | FL | Level 5 | No |