§FMCSR.com
Current textSource: eCFR

§ 393.79 Windshield defrosting and defogging systems.

Current wording, in the annual edition revised as of Oct. 1, 2005.

eCFR (current) ↗
What changedOct. 1, 1996 wording → Oct. 1, 2005 wording (current)+74 added−63 removedHide

Every(a) Vehicles manufactured on or after December 25, 1968. Each bus, truck, and truck -tractor havingmanufactured aon windshieldor after December 25, when1968, operatingmust underhave conditionsa suchwindshield defrosting and defogging system that ice,meets snow,the orrequirements frostof wouldFMVSS beNo. likely103 toin collecteffect on the outsidedate of themanufacture.
(b) windshieldVehicles ormanufactured condensationbefore onDecember the25, inside1968. ofEach thebus, windshieldtruck, and truck-tractor shall be equipped with a devicemeans orfor otherpreventing means,the notaccumulation manuallyof operatedice, forsnow, preventingfrost, or removingcondensation suchthat obstructionscould toobstruct the driver's view: Provided,through however,the Thatwindshield thiswhile section shall not apply in driveaway-towaway operations when the driven vehicle is abeing partdriven.
[70 ofFR the48054, shipmentAug. being15, delivered.2005]

49 CFR § 393.79 — Windshield defrosting and defogging systems.. Text current through October 22, 2026. This wording effective October 1, 2005 to present. Source: eCFR (current), https://www.ecfr.gov/current/title-49/section-393.79. Retrieved from FMCSR.com, https://fmcsr.com/reg/393.79, on October 26, 2026. Unofficial compilation; verify against the official source.

(a) Vehicles manufactured on or after December 25, 1968. Each bus, truck, and truck-tractor manufactured on or after December 25, 1968, must have a windshield defrosting and defogging system that meets the requirements of FMVSS No. 103 in effect on the date of manufacture.

(b) Vehicles manufactured before December 25, 1968. Each bus, truck, and truck-tractor shall be equipped with a means for preventing the accumulation of ice, snow, frost, or condensation that could obstruct the driver's view through the windshield while the vehicle is being driven.

[70 FR 48054, Aug. 15, 2005]

Amendment history

2 distinct wordings on file since Oct. 1, 1996
  1. Oct. 1, 2005 → presentannual editions 2005–2016diff vs. previousviewing
    [70 FR 48054, Aug. 15, 2005]
  2. Oct. 1, 1996 → Oct. 1, 2005annual editions 1996–2004

A new entry appears whenever the regulatory words change between government snapshots. Day-precise from the eCFR (2017 onward); before that, one snapshot per annual CFR edition (revised as of October 1). Bracketed citations are the Federal Register history printed with the section. Set a case date in the header to read any earlier wording.