scope:

Introduction

Note: Nothing in this standard supercedes applicable laws and regulations.

Note: In the event of conflict between the English and domestic language, the English language shall take precedence.

Purpose. To determine if the defrosting and defogging system in a passenger car meets the requirements of:

Canada Motor Vehicle Safety Standard 103 (CMVSS 103) as amended in the Canadian Gazette.

Federal Motor Vehicle Safety Standard 103 (FMVSS 103) as amended in the Federal Register.

Applicability. This test specification applies only to passenger cars. Compliance of multipurpose vehicles, trucks, and buses is validated by review of applicable drawings and requires no testing.

Remarks. This internal procedure is intended to set standards for measuring compliance of GM vehicles to FMVSS 103/CMVSS 103; however, it is not intended to fully duplicate all aspects of the government FMVSS 103/CMVSS 103 as several optional methods are allowed and some parameters remain undefined in the federal document.

Air velocity shall be 8.0 ± 1.0 km/h. FMVSS 103 states 0 km/h to 3.2 km/h air velocity. Higher wind speed is more severe than stated in FMVSS 103 as the vehicle heater removes ice by warming the windshield and the ambient external air velocity removes heat from the warm windshield. A higher air velocity will remove more heat from the windshield, slow the warming of the glass and slow the melt of ice. The effect is similar to the term "wind chill" where cold weather feels colder when the wind is blowing due to additional heat loss.