Headlamp Relays

I was very interested in the recent thread on this so decided to convert my headlamps to a relay system and in the process extend the life of the ignition switch. Being in the UK the Easter Beaver stuff recommended in the other thread was not an economic prospect so I made my own.

To help illustrate some of the process as outlined in the other thread I have included some pics.

I decided to use the existing sub-loom (harness to you USA guys) which goes to each headlight from the main loom. They look like this:-



I was lucky enough to pick up a couple of news ones for £10 (normally £13 each) so I could modify these and have the original ones should I want to go back to stock or screw the conversion up!

I used a pair of Durite mini 30 amp 5 pin relays thus:-



They are about £6 each but you can get much cheaper if you don't use 5 pin ones.
The fifth pin is a second power output pin to avoid using "piggy back" connectors on one pin.

Next...take the old looms out. Here is where they run on the right side of the bike under the plastic headstock/frame tube cover:-



Trace them back to the connectors under the tank. They look like this:-



Next job was to remove the headlamps and unplug the loom at that end (if you have a screen, removing it first makes life easier). Here is the lamp end:-


Guide the loom through from the tank end making a note of the cable route. The connector comes through the headlamp hole after pulling the grommet out:-



Then make up the new loom by cutting into it near the under tank socket end (a bit of measuring up helps to see where the relay fits under the tank) using the power lead (blue/white for dip and blue red for main) to power the relay and the earth (black) to earth the relay. You will need to solder a new piece of cable to the remaining earth lead, insulate it and run it back to the battery for a good earth for the lamps. If the relay is for the dip, leave the blue/white cable free with a connector on the end to connect to the other relay in the other loom. You also need to run a power cable back to the battery to power the lamps via the relay. My finished relay looked like this at the under tank end:-



The single cable by the side of the relay is for connection to the relay on the other loom as each relay powers either the main or dip beam for both lamps. I used soldered connectors, insulated covers and a good helping of silicone grease when assembling the loom as I don't trust crimped connectors that may get damp. For the cables running back to the battery I used the correct colour codes to avoid confusion. I used high performance 1mm thinwall cable
(used on most modern vehicles) which has a capacity of 16.5 amps . I get my stuff from here www.vehicle-wiring-products.eu . They give good service and are good on price As I ran a separate cable for dip and main this will be more than adequate (60watt x2 divided by 12 volts equals 10 amps). I then duplicated the process thus far to make the second loom. To install them, temporarily remove the relays and feed the loom through from the headlight end following the original route (which you noted!) and replace the headlamp grommet. Reconnect the relay (each relay has a helpful diagram on it to avoid wrong connection) and plug the under tank socket in. The relays fit snugly behind the plastic headstock cover just behind the headstock...can you see them?



Next I ran the two power cables and associated earths to the battery and fused each circuit separately. if one circuit blows for some reason I still have light! The fuses tuck under the right side cover:-



Connecting the power cables to the battery was a bit of a problem as I had used soldered ring terminals which meant that the reach of the battery terminal bolts was insufficient to grip. I cut a couple of stainless M6 bolts to 15mm in length and they worked fine! Also, if you have a Datatool alarm, keep the fob handy when messing about with the battery...you will go deaf otherwise!

I then put the tank back down, re-installed the the headlamps and turned them on.....all worked fine! It was notable that the lights do not brighten or fade with engine revs. Here are the before and after pics for you to see if you think there is any improvement in light output. Before:-



And after:-



Bit of a long post I know but I hope someone may find something useful in it.