Stock Aux Lighting... Too much Load?

[ZXPilot]

Here’s an interesting first for me… My local dealer told me the stock aux lights that come on the Heritage are not meant to be turned on for extended periods of time because the headlight cannot handle the current draw. I’m not quite buying the story so I thought I would ask other Heritage owners of their experience.

The problem I’m having with my 12’ Heritage is the headlight bulb blows out after being on the road for approximately 12 hours, which is a normal time period for a good day’s ride in my opinion. The problem has pretty predictable behavior and it came to a head on a trip I took to Waco, TX back in the fall. I went thru three headlight bulbs in five days on that trip. My local dealer has put some serious time into troubleshooting the problem, along with Corporate, but the anomaly is tough to duplicate since it only shows up after about 12 hours of riding. I was hoping to come to this group and share the resolution for this problem but the last word I received from my dealer was to not run the aux lights all day since the system wasn’t designed to operate that long. The theory is the aux lights are putting a strain on the headlight by forcing it to consume too much current. That’s their story.

I’m curious if this is a known issue and I just missed it or if this is a rare but solvable problem. I haven’t had any problems with the aux lights themselves. Just the headlight bulb keeps blowing out (broken filaments). For now I keep a couple spare headlight bulbs in my saddlebag but it sure would be nice not to have to deal with bulb changes. Has anyone else run into this problem? I ran a search on the forum but came up empty. Any insight would be greatly appreciated.

Thanks,
Anthony

[bikedelic]

To say that running aux lights causes too much current through the headlight bulb is an uniformed statement. Current is limited by the applied voltage and resistance of the circuit.

Aux lights are wired in parallel with the headlight and do not affect the current through the headlight since they do not change the resistance of the headlight bulb itself. Total circuit current for the headlight and the aux lighting will be higher, but that would affect the fuse/circuit breaker in an overload condition, not the headlight. The current for the aux lighting does not run through the headlight bulb.

[Lakerat]

I would be looking for a grounding problem.

[mopar]

Total BS. Aux Lights will not cause headlight to draw more current. I have a 2012 Fatboy with aux lights. I run mine all the time. No problems. Maybe a regulator problem.

[Vettster]

So, have you tried not running the auxiliary lights?

That should not be the problem. If they weren't meant to be used it is highly unlikely that the MOCO would have installed them.

Why doesn't the fuse (breaker) blow?

Somethings wrong.

[Dave63]

Originally Posted by ZXPilot

Here’s an interesting first for me… My local dealer told me the stock aux lights that come on the Heritage are not meant to be turned on for extended periods of time because the headlight cannot handle the current draw.

Anthony....your dealer is obviously having a (insert type here) moment.

You need to check the volatge at the headlight plug. It should be no more than 14.7-14-8 volts, or you may have a bad voltage regulator that's allowing more voltage than normal to be subjected to the bulb.

Vibration is another issue with bulbs. The filiments are Tungsten, and burn to produce the light. As the Tungsten burns, the filiment becomes thinner and more brittle. The black residue you see in an older buld is acutally Tungsten residue.

If the bulbs are being placed in the bike with bare fingers, oil from your fingers can cause "hot spots" on the bulb glass, and can cause premature failure. However, 12 hours sounds like a voltage issue to me.

I run my passing lamps 24/7, and have taken 12 hour rides. Still the original headlight bulb. The charging system produces what the bike needs, based on Amp draw and wattage. If there's a faulty ground, or regulator, or even stator, the bike can produce more than necessary electricity, but more over, allow it past the resulator, and effect elecrical items.

I'd also check the ground for the headlamp, as well as the voltage at the plug, and at the battery. Continued high voltage at the battery will cook the battery and shorten it's life eventually.

[bikedelic]

Dave is right: too much voltage or excessive vibration. A poor ground will increase resistance and reduce current, but an intermittant ground can cause voltage spikes as the circuit makes and breaks through an inductive load (ie. coil/relay), thus overheating the bulb. The bulb is more resistive than inductive, but it may be a possibility.

I would have to look at that with an ociliscope to see what was happening. I would look at the output of the regulator first and check vibration and connections next.

[iameasy]

Anthony,

I dont think your stealerships theory is correct,
I run my passing lights, head light, plus another set of 4 1/2 in passing lights on my crash bars all the time on my 05 softail with no problems. [ 5 lights burning continuesly]

[ZXPilot]

Thanks for the replies guys... I hope you don't mind me consolidating my replies in this message.

Overall... Yeah I thought the fertilizer was being laid down pretty thick but it's good to get a sanity check every so often. I've never personally met a respectable engineer who has ever designed and deployed a system without a good amount of headroom in the operational limits. That just doesn't sound like a good practice at all which is why I was surprised by the direction to not use my aux lights.

My original thought after the Waco trip was the voltage regulator as Dave63 and bikedelic have mentioned but my dealer pushed back hard on that possibility since my regulator doesn't fall within the "range" of bad regulators that were distributed in mid to late 2011 and early 2012. I guess they don't understand electrical components can and do fail on their own. Anyway I'm figuring after five visits to the dealer where they've checked for bad grounds and a faulty harness I must be looking for an intermittent active component problem.

Vettster, I too am curious why a fuse hasn't blown. I have a shop manual so I should be able to trace the circuits to determine the answer to that question. I have run without the aux lights during the day but I haven't been on a long ride since my return from Waco in September. I'm overdue...

Dave, I performed some voltage checks earlier on and I seem to recall 14.3 volts being the norm with the bike running. I will take the readings again and write them down this time. I definitely didn't think about a potentially bad stator though. It is possible for windings to spike intermittently given the right conditions so that is something I need to look for as well. I had to LOL in regards to handling the Tungsten bulbs. Very early in my career I set back a pretty high profile thermodynamic experiment for a few hours because I touched a few heaters (tungsten bulbs) with my bare fingers in a moment of inattention. There are some things a person doesn't forget. I break out a cotton cloth when I need to handle the tungsten bulbs. I keep one in a ziploc bag in my left saddle bag just in case :-)

bikedelic, thanks for the information on the aux lighting wiring configuration and the reminder. I have an old Tektronix 465 sitting around in my garage I can put to use. That used to be my go-to instrument for everything electronic\electrical years ago so I'm surprised I forgot I had it.

Well... I was hoping the dealer would get the issue sorted out so I wouldn't have to work it but it seems that canal has run dry. I will take your guy's suggestions and start with some voltage readings and ground checks and then press on from there. I think I may replace the voltage regulator anyway since my gut tells me it is the culprit. If the problem still persist I'll just have a spare. I'll keep you informed on what I discover.

Thanks again,
Anthony

[ZXPilot]

Originally Posted by iameasy

Anthony,

I dont think your stealerships theory is correct,
I run my passing lights, head light, plus another set of 4 1/2 in passing lights on my crash bars all the time on my 05 softail with no problems. [ 5 lights burning continuesly]

Hey there iameasy,

Five lights... that's impressive. Now that is definitely more proof that my ride has a problem that really needs to be addressed. Thanks for sharing your lighting configuration.

I have to laugh at this whole experience. I just remembered that along with being told not to run my aux lighting I was also told to stop using the H-D performance bulbs as well. It appears I need to stop listening to my local dealership go back to working on my own bike which I have done faithfully up until I purchased the Heritage.

Anthony