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Reading the regulations as they stood on October 1, 2016. Current text may differ.Switch to current
Current textIn force on Oct. 1, 2016Source: annual CFR editions 2005–2016

§ 393.79 Windshield defrosting and defogging systems.

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

govinfo, 2016 edition ↗
Before Jan. 1, 2017 the record is one snapshot per annual CFR edition, revised as of October 1. This is the 2016 edition's wording. An amendment that took effect between Oct. 1, 2016 and Oct. 1, 2016 would not appear until the next edition, so check the citations below and the Federal Register for exact effective dates.
49 CFR § 393.79 — Windshield defrosting and defogging systems.. Text in force on October 1, 2016. This wording effective October 1, 2005 to present. Source: govinfo, 2016 edition, https://www.govinfo.gov/app/details/CFR-2016-title49-vol5/CFR-2016-title49-vol5-sec393-79. Retrieved from FMCSR.com, https://fmcsr.com/reg/393.79?asof=2016-10-01, 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.