§ 773. Operating Requirements.

(a) Normal Operation. When headlamps are operating normally, the headlamp outage indicator shall operate at not less than 10% nor more than 20% of the normal voltage used to indicate an outage. When taillamps are operating normally, the rear lamp outage indicator shall operate only when the foot brake is applied.

(b) Circuit Failure. When lamps are turned on, the outage system shall respond to circuit failure by continuing the normal display of any unfailed lamp, energizing the appropriate inactive lamp filaments, and indicating the failure to the driver. A “headlamp circuit failure” exists when one-half or more of the upper or lower beam filaments have failed. A “taillamp circuit failure” exists when one-half or more of the taillamp filaments have failed. A “stoplamp circuit failure” exists when the stoplamp switch or fuse fails.

(c) Headlamp Outage. Failure in the lower beam headlamp as defined in preceding subsection (b) shall cause the outage system to activate the upper beam circuit at a decreased voltage. Failure in the upper beam headlamp shall cause the outage system to activate the lower beam circuit at a decreased voltage. Such failure in lower or upper headlamp beam shall be indicated by the continuous steady-on or flashing of the headlamp circuit outage indicator.

(d) Taillamp Outage. Failure of the taillamp circuit shall cause the outage system to activate the stoplamp circuit at a decreased voltage. Such failure shall be indicated by the continuous steady-on or flashing of the rear lighting outage indicator at not more than one-third of its normal brilliancy.

(e) Stoplamp Outage. Normal activation of the stoplamp circuit shall operate the rear lighting indicator at normal brilliancy during application of the service brake. Failure of the stoplamp filament, switch, or fuse shall cause loss of this indication.

(f) Alternate Circuit. Reserve lamps in the alternate circuit shall be capable of automatically performing the design function as well as compensating for the outage.

(g) Operating Unit Voltage Drop. Voltage drops across headlamp and rear lamp sections of the operating unit shall not exceed the following values for each normally operating function when the lamps are operated at design voltage:

0.40 V for two lamps

0.45 V for three lamps

0.50 V for four lamps

0.60 V for six lamps or more

Note

Note: Authority cited: Section 26103, Vehicle Code. Reference: Sections 24012 and 26103, Vehicle Code.