Get Your Headlight Working In An Emergency With The Hunt Shunt

A Quick Way To Get Light Back On The Road In Some Emergency Situations


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Thanks to Jim (Beau) Hunt

So, there you are getting set to take off for the journey home or you're out with a group. It's getting a little late, sundown coming soon and you notice that you do not have headlights! This is a problem but not to despair, we will get you on your way.

It should be noted that this is an emergency procedure and assumes that the bulb is good (normally a headlight will only blow out one filament so you'd have high or low beam left) and that no connections have come loose. It will show you an easy test to perform to determine if this will work for you and at least get you home to further diagnose the problem and the reason(s) for it.

As shown in the photo at the top of the page, although the bike is running there is no headlight. Luckily the driving lights are on a separate circuit. You might not be as fortunate if you had connected your driving lights to the headlight power source (find more on that issue on this Gadget page).

 

What You'll Need

  • A short (about 2") piece of 16 to 18 gauge (or approximate) wire. This is an emergency procedure; a piece of bailing wire or paper clip would suffice.
  • A 12 volt test light or multimeter. If you don't have a test light, it's the middle of the night, no auto supply or hardware stores around you can use a piece of wire and one of your turn signal or brake bulbs.

 

How To Do It

  1. hs1.jpgRemove the right side cover located just below the seat. There is onehs2.jpg Phillips screw holding it, it then simply pulls straight out and is held in place by two rubber grommets. This will reveal the junction box/fuse holder as shown at right.

    Having removed the junction box cover by grasping the top of it and pulling out, you can now see the fuses and two connector plugs.

  2. Visually or using the 'continuity' function of your multimeter, check the headlight fuse (refer to diagram inside the box cover). It will be the fuse on the left of the bottom row.
  3. Fuse okay? If not replace it and go ride but check your headlight frequently, there's reason the fuse went on you. If the fuse is good we'll move on. Using the test light or multimeter, check for power going to the headlight circuit. Turn the ignition on, bump the starter button (there's normally no need to fully start the engine to close the headlight relay). Test for power coming out of terminal #8 which has a blue/yellow wire. (inside row 2nd from top,bottom connector) as shown at right.

    If there is no power indicated here, you know that the headlight relay (inside the box and not serviceable), has no power coming out of it which could indicate a bad stator, or rectifier/regulator (discussed later). Or of course, the relay itself may be bad and require replacement of the junction box.
  4. hs6.jpgIn your poking about you might have noticed there is an unused terminal (#7) in the adjacent row where you found the blue/yellow wire. (outside row, bottom) This is powered whenever the ignition is on. (Go ahead and test it with your test light).
  5. Now we are going to run a short jumper wire between those two terminals i.e. #8 to #7 by simply inserting each end into the appropriate terminal. I used a small male terminal bullet on the end going inside the terminal with the blue/yellow wire (#8), but you could probably get by with just the bare wire ends of the wire. (ahh, you “might” want to turn your ignition off first!)

    Once your jumper is in place as shown in the photo at left turn the ignition back on. With any luck it's VOILA! Lights!!!

    Notice they will now come on as soon as the ignition is turned on and the bike does not have to be running. The reason for this is you've bypassed the headlight relay that acts to keep the headlight off while starting the engine to minimize battery drain.

Now, the why... although this procedure will work and give you lights, you need to find out what happened. Your headlight relay could be bad and you need a new junction box, or…. you might have a bad stator and/or rectifier/regulator, which is not producing enough power to power an otherwise perfectly good relay. It should also be noted that I always carry a small, test light and/or multi-meter onboard. Although I went into a lot of detail here, it is actually very easy and will take no more than ten minutes, or if you are brave, eliminate the testing altogether, just stick in the jumper wire and be on your way in about 2 minutes! BUT…. IF YOU ALREADY HAD POWER THERE, I DON’T KNOW WHAT WOULD HAPPEN! (probably nothing more than popping a fuse).

P.S. Thanks to Wadjo, VROC #12931 for discovering the extra terminal #7. He did something similar but relocated the wire feeding the headlight circuit. I merely took a “short-cut” (pardon the pun).

Tag: lighting

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