Left headlight bulb not working

Hyzakp

Hyzakp

Joined
Apr 27, 2013
Messages
28
Location
Taylor, Tx
Bike
08 St1300
Both high and low beams on the left bulb quit at the same time. Is this a bad bulb or something else. Noticed that the high beam indicator light doesn't work even though the high beam on the right side still works. Was just going replace the bulb but can't get the socket disconnected. What's the secret? I'm sure that there is some kind of latch but can't figure out how it works. Not much room to work in that area. Should I be checking relays instead of just changing bulbs?

Pat
 
The first and easy thing would be to pop out the bulb and look at it. Its not normal for the Hi and Low to go at the same time but it could happen.
 
What is weird on the ST1300 is that the Right bulb is fed from the dimmer switch and the left is from the dimmer switch to relays to the left bulb, I ran into that bizarre arrangement putting on a headlight modulator. And it is in the Honda workshop manual also. You may have a bad relay or 2.
 
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My vfr has been blowing bulbs lately too, checked the RR and its fine,hard to know what the cause is,not much room on the vfr either.
 
Check your fuses first if they are good pull the bulb by reaching up and squeeze the ends of the plastic and remove the wires, pull metal stay and remove bulb, replace and ride.
 
It's not the bulb I'm afraid. Not with both high and low gone at the same time along with losing the hi beam dash indicator light. Sometimes the drain hole in the depression under the relays plugs up and standing water accumulates. The lowest relay is the lo beam and standing water corrodes the wires leading into it. I had this issue and ended up having to replace the terminal ends of a couple wires before the left light headlight worked again.
 
970mike said:
Check your fuses first...
Click to expand...
Yes, most likely the 10amp fuse (labeled H/Light) has failed.

This fuse provides +12vdc to both the low-beam and high-beam relays, which in turn, provide +12vdc to the left-hand headlamp. The fact that both low & high beams have failed suggests either a fault with the +12vdc supply to the relays, or a simultaneous fault with both relays. Additionally, the fact that the high-beam indicator is also not functioning properly (Note: The high-beam indicator is driven by the left-hand headlamp high-beam circuit, and does not require a local connection to ground.), also suggests that this is a +12vdc problem, and not a 'ground' related problem.
 
Anna'sDad said:
Yes, most likely the 10amp fuse (labeled H/Light) has failed.

This fuse provides +12vdc to both the low-beam and high-beam relays, which in turn, provide +12vdc to the left-hand headlamp. The fact that both low & high beams have failed suggests either a fault with the +12vdc supply to the relays, or a simultaneous fault with both relays. Additionally, the fact that the high-beam indicator is also not functioning properly (Note: The high-beam indicator is driven by the left-hand headlamp high-beam circuit, and does not require a local connection to ground.), also suggests that this is a +12vdc problem, and not a 'ground' related problem.
Click to expand...
If it is the fuse then both left and right headlights would go out. If the RH light is working the fault is not likely the fuse....there is no left/right or hi/lo headlight fuse....just one for both lights.
 
dduelin said:
If it is the fuse then both left and right headlights would go out. If the RH light is working the fault is not likely the fuse....there is no left/right or hi/lo headlight fuse....just one for both lights.
Click to expand...
The headlamp wiring circuit for the Honda ST1300 is a bit odd. However the circuit does indeed use two distinct fused circuits to provide +12vdc to the headlamps:


1) Fuse D (ABS Fuse E), labeled 10A H/Light, and located in the forward fuse box, provides +12vdc to the right-hand headlamps, via the Starter Switch, and the Headlamp High/Low Beam Switch, as well as the control circuit (coil) for the left-hand headlamp relays. This bit of circuitry is not ideal in that when this particular fuse fails, both left-hand & right-hand headlamps will go out.

2) Fuse G (ABS Fuse I), labeled 10A H/Light, and located in the rearward fuse box, provides +12vdc to the left-hand headlamps, via the Headlamp High Relay & the Headlamp Low Relay (contacts). This circuitry is more user friendly, as when this fuse fails, only the left-side headlamps go out.

Here's a sketch of the headlamp wiring as used on the Honda ST1300.

Hyzakp said:
Both high and low beams on the left bulb quit at the same time.
Click to expand...
The loss of Fuse G (ABS Fuse I) would appear to be a reasonable explanation to the original problem.
 
Anna'sDad said:
The headlamp wiring circuit for the Honda ST1300 is a bit odd. However the circuit does indeed use two distinct fused circuits to provide +12vdc to the headlamps:


1) Fuse D (ABS Fuse E), labeled 10A H/Light, and located in the forward fuse box, provides +12vdc to the right-hand headlamps, via the Starter Switch, and the Headlamp High/Low Beam Switch, as well as the control circuit (coil) for the left-hand headlamp relays. This bit of circuitry is not ideal in that when this particular fuse fails, both left-hand & right-hand headlamps will go out.

2) Fuse G (ABS Fuse I), labeled 10A H/Light, and located in the rearward fuse box, provides +12vdc to the left-hand headlamps, via the Headlamp High Relay & the Headlamp Low Relay (contacts). This circuitry is more user friendly, as when this fuse fails, only the left-side headlamps go out.

Here's a sketch of the headlamp wiring as used on the Honda ST1300.

The loss of Fuse G (ABS Fuse I) would appear to be a reasonable explanation to the original problem.
Click to expand...
I stand corrected. Pulling fuse G does disable the left hand headlight on both hi and low beam and disables the high beam indicator on the dash. If it is not the fuse it could still be a faulty ground in the LH headlight connector. I've seen this on two ST1300s.
 
Thanks for all the responses guys. It was just a blown fuse. I don't know why I did not check this first once I removed the bulb and saw that it was still good. The fuse should have been the next logical thing to check. However there were no spares in the fuse boxes. Is this a regular thing or just something random? Had the bike a year now and that's the first blown fuse.

Pat
 
Ok, not sure when it happened but it appears that the fuse is blown again. Normally this would indicate a short somewhere but I know that it didn't blow immediately. I will replace the fuse and see what happens. Does anybody have an idea where my issue might be? Just curious if there is an area that the wiring could be getting rubbed through.

Pat
 
Hyzakp said:
Ok, not sure when it happened but it appears that the fuse is blown again. Normally this would indicate a short somewhere but I know that it didn't blow immediately. I will replace the fuse and see what happens. Does anybody have an idea where my issue might be? Just curious if there is an area that the wiring could be getting rubbed through.

Pat
Click to expand...

Pat you need to take a look at the wires running to the headlamps as they have to have a short in them more then likely around the steering head look for a pinched wire.
 
Hyzakp said:
Was just going replace the bulb but can't get the socket disconnected. What's the secret? I'm sure that there is some kind of latch but can't figure out how it works.
Click to expand...
Take a look at this thread on changing headlamp bulbs, or just jump to the post with the picture.

On the other hand if you still have difficulty disconnecting the headlamp connector (and fuses continue to fail), then you may have a connector problem. I replaced a headlamp bulb connector due to a poor connection on the ground terminal. the connection had developed a high enough resistance that the plastic connector shell melted, as well as the insulation on the ground conductor for a number of inches. It was unclear as to what exactly had caused the increase in resistance, however a new connector with six inch pig tails solved the problem. I don't know that you have this issue, but a high resistance (in addition to the filament resistance) could be enough to cause a fuse to blow.
 
I had similar trouble with my left headlamp, I replaced the whole pig tail from the connector, there may have been a short in there. It was easier to just solder in a new one. I got the bulb socket from an auto parts house and soldered on the Honda connector. Haven't had a single bulb blow out since.
 
I still have not resolved this issue. Even with the ignition turned off I have 12 volts across the fuse I contacts. This indicates that a hot wire is grounded to the frame or a ground wire somewhere in the harness. Any body have an idea where this might be occurring? At least this is not keeping me from riding as the right side headlight is still functioning.
Pat
 
Hyzakp said:
Even with the ignition turned off I have 12 volts across the fuse I contacts.
Click to expand...
Yes, that is correct. Fuse I circuit is not disabled by the ignition switch.


Hyzakp said:
Any body have an idea where this might be occurring?
Click to expand...
If the fuse is 'blowing' with the ignition switch off, try removing both LH Headlamp relays.

With the relays removed, the circuit for Fuse I terminates at the relay sockets, thus if the fuse 'blows' in this scenario, it's a pretty good indicator that the fault is within the wiring harness running from the Fuseblock to the relay location. That shouldn't be too difficult to trace out.

If the fuse doesn't 'blow', then you may have a faulty relay, try reinstalling one of the removed relays, check the circuit, if the fuse 'blows', try the other relay.

With the ignition switch off, it should be that easy!


On the other hand.

If the fuse 'blows' only with the ignition switch on, the circuitry 'down stream' of both relays comes into play. Try reinstalling one relay for a period of time, this will assist in determining which of the two circuits (high-beam or low-beam) is causing the problem. Both of these circuits are in the main wiring harness that terminates in a 24-pole connector at the steering head.
 
Look at the wire loom on the left side of the frame between the left glove box and frame. I will try to find a picture of my loom that had bare wire showing through the insulation. Upon turning the bars full left the wire loom would contact the frame and take out the headlight fuse.

Click here for the picture.
The culprit to cause this damage is that pointed clip retainer for the Clutch line. One other member had her bike in the same condition as mine when my problem was found at the Pardeeville TechSTOC in 2010.
Credit for this find goes to DannyK.
 
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Found the short. Actually found it quite by accident. I was moving the harness around to disconnect the relays and saw an arc where the harness comes down near the left hand side of the lower fuel tank mounting boss. Apparently this had rubbed through over time causing an intermittent ground. This explains why I could replace a fuse and it would hold for a period of time and not immediately fail. After insulating the bare wire I wrapped this part of the harness with some of that plastic shielding to protect it.
Thanks to all for your responses in tracking down this problem.
Pat
 
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