Headlamp circuit and relay

[heavenly7]

I think it is standard to have a two way toggle switch that switches the headlamps from full beam to dip.

 

I want to replace the toggle switch with a push button switch - replicating the two way function - pressed beam up, released, dip.

 

With my elementary electrical knowledge I thought a five pin relay might do the job of switching with the three pins 87a, 30 and 87 taking the existing three wires to the toggle switch and 85 and 86 running to the press button switch - but it doesnt activate the relay to switch between the two.

 

I have a sneeky feeling that I need a negative feed.

 

What is the best way of achieving the correct result please? (and why )

 

 

[Johnty Lyons]

It sounds as if your using a latching PB, a) press cct made b) release cct broken. if this is used to energise a CO relay and that relay just replaces the toggle sw it will work 100% Where it gets a bit more complicated is if you are using a simple non latching PB which only either makes or breaks momentarily. That will require a more complex cct with a bit of electronics.

In your simple cct the relay will need a neg to one side of coil and your PB will link feed from headlight sw to other side of coil thus PB will energise de energise relay alternatively the three contacts on relay will then just replace the three wires on the existing Dip/Main toggle sw

 

Edited by - Johnty Lyons on 5 Oct 2010 23:27:40

[heavenly7]

Johnty

 

Thank you.

 

I have the wires that ran to the light bulb in one of the gauges I no longer use; presumably this would provide a +ve and -ve feed to the coil via the press switch.

 

Edited by - heavenly7 on 6 Oct 2010 00:23:08

 

Edited by - heavenly7 on 6 Oct 2010 00:31:30

[alan7]

Try this:

 

Fused power supply to PB switch (From your old light)

Output from PB switch to pin 85

Power supply from headlight switch to pin 30

Earth to pin 86 (From your old light)

Dipped headlight supply to pin 87

Main headlight suupply to pin 87a

 

PB ON = the relay coil is powered & pin 87 is connected to pin 30

PB OFF = the relay coil is NOT powered & pin 87a is connected to pin 30

 

Hope it helps

 

Edited to add

 

Yes, the (+) & (-) from the light you no longer use should be adequate BUT it will only be live when the side lights are switched on & the rest of the guage lights are on.

 

 

Edited by - alan7 on 6 Oct 2010 00:43:48

[Johnty Lyons]

If you wanted to be clever fit an ign control relay into the feed from your side lights to the head light switch Kills the headlights and saves the battery when ign/eng is off 😬 😬