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Headlight issue?

9K views 52 replies 13 participants last post by  calebj 
#1 ·
I'm really new at this, so if this is a stupid question, I apologize ahead of time.

When I set my light dimmer switch to the low beam setting, the headlight dims to about the brightness of parking lights on a car, and the headlight failure light comes on. If I set the switch to somewhere between Hi and Lo, the failure light shuts off, and the headlight seems to be lit at about the regular low beam brightness. If I set the switch to Hi, the high beam light comes on as normal, and the headlight seems to be as bright as the high beam should be.

My question is, is this normal? What I gather from reading the manual is that this is not normal. My VN is from 1998 and I bought it used. Could it be the result of a mod the previous owner did?
 
#3 ·
It sounds to me like your bulb is bad....low beam may be burned out.
The Reserve Lightning Unit is using your high beam element at half brightness to cover the low beam....because the low beam is burned out.

This is normal....the RLU was designed to do this so you would still have some light when the bulb burns out.....replace the bulb.

As far as having any contacts or lights with the switch in the half between hi and low.....that is not how it was intended to be used.....that is just an incidental observation.
 
#6 · (Edited)
Hey, I will sell you the new bulb I needlessly bought when I had the same symptoms.

Is dim, really really dim? If so, that is not the way the RLD works. When you burn the low element, the RLD should automatically transplant the high beam @ reduced voltage.

edit- I would test the bulb w/auxiliary power source. I plugged mine into my '92 S-10.
 
#8 ·
With dimmer than expected lights (filament type bulb which we have) it's usually low voltage. If the problem is only at low engine rpm's (under 1500 rpm) it could just be a weak battery (several potential causes but probably just a bad battery). If the headlight is still dim at higher rpms you probably have a problem with your charging system.
With the filament type bulbs we have they generally work or they don't so I doubt it's a headlight issue although a loose or corroded headlight wire connection could do it but unlikely. Get a voltage meter out and test your voltage to the battery with the engine over 1500 rpm. If it's below 13v you've got a charging issue.
 
#10 ·
"and the headlight failure light comes on"

This was the obvious clue. The headlight indicator on the dash will only come on fully bright when a filament is out. I believe that over thinking troubleshooting issues is not helping......go for the obvious stuff first.

And I would suggest replacing it with a Silverstar Ultra bulb.
 
#11 ·
SilverStar Ultra 9003/HB2 H4 Headlamp...
available @ Walmart or Auto Parts Store.
I purchased a Pair for $2.00+ more than a single, I still have a spare. LOL

:smiley_th
 
#12 ·
Well I just replaced the bulb. Still no difference. The low beam filament is really dim and the failure light comes on when the switch is all the way on lo, it lights up to normal brightness and the warning light shuts off when you move the switch up a little bit towards hi, and then switched all the way to hi, the high beam works like normal. Could the problem be the switch itself? I can get the low beam to work normally, so it's not a huge problem, but it's just kind of annoying that I have to find a sweet spot if I want to use the low beam.


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#13 ·
have you tried switching from hi to low beam multiple times (with power off, then with power on) in an attempt to clear off any oxidation of switch contacts?

Kenny
 
#16 ·
Well....it appears you will need to open up the switch to clean it.

Sorry if you feel that buying the bulb was a waste of money.....at least you have a spare now.
 
#17 ·
Well....it appears you will need to open up the switch to clean it.
I'll throw the X2 on that, since you have to find a sweet spot in the switch to get the low beam, the contacts must be misaligned and/or dirty. I'm pretty sure these switches have been cleaned or repaired successfully, should be some past posts on it.

You could try some contact cleaner and repeated switching back and forth, or just try it without a cleaner, but there's usually no substitute for getting eyes on the problem spot.
 
#18 ·
Luckily, that's not happening here. Hi is just the high beam filament, Lo is just the low beam filament, either dim with the warning light, or a normal low beam brightness without warning light, depending on whether or not I've hit the "sweet spot" on the switch.
Edit/Delete Message
This sounds like a problem with the Reserve Lighting Unit. The Low beam light is supposed to faintly burn when every thing works, but not the way you are describing.
 
#19 · (Edited)
I've been waiting for you (Slim) to post...you are almost always correct in your advice. :p

:smiley_th
 
#20 ·
I agree with Slim's thinking, but if you don't get to the contacts in the ignition puck, you won't know for sure. The RLU is not repairable....and to be honest I have not heard of many failing.

try THIS first and if it doesn't help then we can go from that point forward and continue troubleshooting it.
 
#21 ·
Kc, I agree that the rlu failure is rare, and usually so far from my mind that I wouldn't even consider it, but three members thus far this year, have had bad RLUs. Yes check the ignition switch, butt you are going to see it's working finger, along with three headlight switch contacts, because the headlight is coming on and using the correct filament. The only problem being experienced is low voltage at the headlight which would be caused by the RLU or bad wires from the RLU to the headlight.

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#22 ·
Slim, I am not sure if there is a procedure to test the LRU. I will try to look at the schematics and manual to see if there is a way to actually test the LRU and report back if I come up with it.

To the OP...if after cleaning the ignition switch you still experience the same issue, let us know and we will go from there.
 
#25 ·
the dimmer switch is a strip of copper (thumb button) and two contacts, High and Low Beam... when you find that sweet spot, you are applying power from the high beam to the low beam side and bypassing the RLU. a

The RLU defaults to low voltage on the low beam side diverting power from high beam to low beam, so if its failed, you would get exactly what you are seeing.
 
#24 ·
I have looked at the headlight wiring schematic over and over and over again, and I still do not see how cleaning the ignition switch would possibly fix this.. the headlight power feed comes through the ignition switch to the headlight relay, out of the relay and back to the RLU, then from the RLU to the headlight switch, from the switch to the headlight high and low beams. The RLU is a voltage sensing device as well as a voltage reducer. you should be getting 12 volts out of the RLU on all wires except the light green/red and the black/yellow. If the voltage is less than 12 volts on the black/red wire (which it sounds like it is) and 12 volts or higher on the light green/red wire, then the RLU is not functioning correctly, or the headlight low beam filament is burnt out. The OP already replaced the headlight, so that eliminates that and points to the RLU.



 
#31 ·
I was curious what was the outcome of this issue.
Did the OP sucessfully bypass the RLU according to the instructions Slim gave and left it at that, or did some other solution present itself.

Feedback on these types of issues are important to us so we can learn from them and document these things in order to help others with similar issues.
Please follow up if you can.
 
#33 ·
Based on my very confused understanding of the wiring diagram, that makes sense to me. You should be able to move the Blue terminal on the 8 pin connector at the JB to eliminate the headlight relay, and jumper Blue to Blue/Orange on the connector for the RLU to pass power directly to the dimmer switch.
 
#37 ·
You should be able to test it in <5 minutes. 10mm bolt to drop the right side cover, unplug the RLU, stick a paperclip or jumper wire between the two terminals on the incoming connector.
 
#38 ·
I know but I'm working. Plus that means remove the bunji chords holding the cover on, remove the cover, remove the seat, reinstall the battery, do the test, remove the battery, put the seat back on, put the cover back on, bunji that crap cover back down... See my point haha
 
#40 ·
Haha I knew that was coming. I just did the 2 wire mod the other day and hadnt had a chance to give it a good test ride yet so I still have the battery out and charged up from that. Plus Im planning on installing a volt meter prior to this test ride. I dont have an outlet outside so every time I want to put the battery on the tender, it has to come out and go into my apt w me.... Yea not ideal. NEED A GARAGE!!!:|
 
#41 ·
Strangely enough, I jumped the blue and blue/yellow and the light didnt work at all. I brushed the connections off a bit, plugged it back in and boom the damn low beam works again. I'm not saying it's fixed but if that was it... I feel dumb hahhaa
 
#42 ·
Glad you got it working!

At the RLU, the blue wire is voltage in from the JB, and the blue/yellow is normal voltage out to the dimmer switch, powering both the low and high filaments. Cleaning these contacts should not have done anything, but you may have jiggled one of the other leads on the RLU, like the red/blue high-beam monitor wire, that caused the RLU to start working right again. *shrug*

As for the earlier suggestion about jumping to the blue/orange wire, that wire normally provides no voltage to the dimmer switch. It outputs voltage when the RLU determines that there is no current flowing through the selected filament, causing the un-selected filament to get voltage, basically swapping the high and low beam selection made on the dimmer switch.
 
#47 ·
I am saying that after the engine is cranked, the headlight low-beam turns on in the headlight bulb up front and the white idiot lamp on the dash lights up as well. Then when i push the little switch for high-beams, the high-beam in the bulb lights up and the high-beam idiot light on the dash turns on and the low-beam idiot light in the dash turns off.

I figured that was just the way it was supposed to be to let the rider know the lights were working and which set was on so that highway riding at night would be lampily "polite". . . erm... just like a car.
 
#49 ·
Pretty sure the PO mod this bike electrically. His handy work is everywhere. ( the actual base reason i decided to rewire the harness from scratch ).

But on the other hand... i kinda likey it this way. Ifn the bulb goes out, then the idiot light goes out, then fine... i would "get it". Ima master ub idiot lights, ya nose?
 
#51 ·
It would be easy enough to wire the headlamp MIL directly to the low beam, but seems kind of pointless in this case. On my own bike I had to bypass the RLU because of the LED headlamp so I'm going to use the MIL as an indicator that my driving lights are on.
 
#52 ·
The MIL are.... ____ Idiot Lights i presume... and after you fill in that blank, poke Thorn in the side ( grins ) and get him to add it to the Ofeeeshul VN750 nomenclature glossary, please.

On the presumption that MIL is ___ Idiot Light...

( MIL to me is always "Mil Spec" but... even better... LOL )

All that you would need to do... to get that operational is... get a cheap LED ( Allied Electronics online... less than a buck with SPECS ) then determine the resistor to use ( ask me if you need ), then shove that puppy in the dash and pull the old bulb out, and hook it either....

in series with the LED headlamp: not such a good idea but can be done... OR.... in PARALLEL which makes more sense to basically test that the switch is functioning. Does that lamp run through a relay? I forgot... if so, then best way to run in series, and easy, is just put it in the primary of the relay in series. that would basically test both the switch and the relay at the same time. The light should be easy to know if it's on except in the day anyways... i mean the LED "bulb".

To design in series... directly... you'd need the specs of that LED headlamp, and/or test them yourself to see how much current is passing through it.

hope this helps.
 
#53 ·
MIL is short for malfunction indicator lamp. Not sure where you were going with the rest of that. Were you trying to explain how to solve a problem I didn't know I was dealing with?
 
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