invertor u5d which complements or inverts the 10 hz signal before application to an augmented solid state switch 21 which generates a 10 hz power output signal corresponding to its 10 hz signal input which output is in turn applied to headlight taillight lp3 when the ambient light level falls below threshold i e at night the switch q1 is disabled and a logic low signal is therefore applied to the first input of and gate u8c in this condition night time a logic signal to the second input of and gate u8c does not affect the logic low output signal from and gate u8c which is applied to an invertor u5d which in turn applies a logic high output signal to pin 5 of augmented solid state switch 21 which therefore supplies steady state power to headlight taillight lp3 accordingly the headlight only responds to the 10 hz signal output from and gate u8c during daylight hours and remains in a steady state 0n condition at night without regard to the output of the horn switch s1 in the event of a failure of the light activated switch q1 or indeed of any hazard circuit components switch s3 may be closed so that the headlight has.