Original submission by T Apr 7th 2007:
The circuit allows 4 way Hazard Lights to be added to an Old Holden which traditionally didn't have them. The 4 blinker lights flash on and off together anytime the Hazard Switch is activated.
The diodes permit current to flow into the appropriate areas of the wiring without flowing into the inappropriate ones (they only permit the current to flow in the direction they point). Diodes are Dick Smith cat number Z3229 or any power diode capable of carrying 10 amps and with a Peak Inverse Voltage in the hundreds. This is overkill plus because diodes are dirt cheap and these heavy duty ones are more likely to endure Alternator spikes and jump starting and welders etc. The Diodes can be connected into the circuit using blue crimp lugs. Hazard Switch Thread
Hazard Light Flasher Can:
The hazard flasher needs to be 80 Watts or any universal Wattage type that can handle 80 Watts.
An indicator light can be incorporated inside the hazard switch, Or it can be added between the supply side of the hazard flasher and ground. It can also be connected in parallel with the Hazard Flasher Can. Lights 1 and 3 will flash out of phase with the external blinker lights and dash indicators. Light 2 will flash in phase with the external blinker lights and dash indicators whenever the Hazard Light Switch is activated.