08 GL1800 headlights only work when in reverse

[comjoe1]

I have a 2008 GL1800 with a problem I have seen in several older posts on this site. The headlights only work when the bike is in reverse. Unfortunately the light is pointed the wrong way to ride in reverse all day, . I have tested every fuse in the box and they are all fine. I have taken apart the right side switches and soaked them in contact cleaner. I have tried pulling back on the starter button to no avail. What I find interesting is that when I put the bike into reverse the lights don't come on immediately, there is a short delay while I can here the mechanism switching into reverse. True to what I have read, the high/low switch doesn't do anything, only the 2 low beam lights come on. Is there some sort of sensor on the actual mechanism that puts the bike into reverse or should I start looking to (ugh) replace the starter switch?

[WingAdmin]

More often than not, when you have weird, unrelated electrical issues, the problem is a bad ground. Power will find a path to ground any way it can, so if a ground is bad, and the reverse system suddenly presents a ground, it will use that, and the headlights will work.

[Techdude2000]

I have a 2008 GL1800 with a problem I have seen in several older posts on this site. The headlights only work when the bike is in reverse. Unfortunately the light is pointed the wrong way to ride in reverse all day, . I have tested every fuse in the box and they are all fine. I have taken apart the right side switches and soaked them in contact cleaner. I have tried pulling back on the starter button to no avail. What I find interesting is that when I put the bike into reverse the lights don't come on immediately, there is a short delay while I can here the mechanism switching into reverse. True to what I have read, the high/low switch doesn't do anything, only the 2 low beam lights come on. Is there some sort of sensor on the actual mechanism that puts the bike into reverse or should I start looking to (ugh) replace the starter switch?

Pull out on your starter button. If they come on, then you need to spray some plastic safe contact cleaner into the top of the button and work it until it fully returns to the out position with the lights on every time it’s released. The starter button switch kills the headlights for starting and when it gets dirty, it will fail to fully return, keeping the lights off. It’s bypassed in reverse.

[comjoe1]

Thank you for the tip but I have pulled, pushed, wiggled, jiggled, and otherwise moved the starter button in all directions. I even took it apart and cleaned it extensively with contact cleaner. I could not make the lights come on.
Do you know of some way I can test it perhaps by jumpering some wires to bypass that circuit to prove it is the starter switch? I Really don't want to go through the work or expense of changing that out to find out it was a different problem.

[Techdude2000]

Ok, so they work in reverse, that tells us the bulbs and the low beam relay are OK. You said the high beams won’t come on either, so this narrows the issue down to the headlight main fuse, the starter button switch, or the associated wiring and connectors. Start with the headlight main fuse (10A). The only other thing this fuse powers is the headlight height adjustment motors. They have been known to malfunction and blow this fuse, so checking it is a good idea. If it’s good, then you will need to drop the bottom on the handlebar control pod and check for power on the brown/red wire at the starter switch. There should be power on it with the key on. It should also be on the blue/white wire as well if the switch is good and passing it through. If it’s there on both wires, then we will need to investigate the control pod connectors under the right fairing pocket for corrosion(C17, C18)

[comjoe1]

Thanks for the info. I will look at that this afternoon and let you know.

[comjoe1]

Checked the fuse. It is good. Dropped the bottom of the right side switch pod. It looks like there are 4 wires going to the start switch, black/white, yellow/orange, brown/red, and blue/white. Turned on the key and checked for power. The only wire that showed power is the black/white one. All others were dead. Where do I look next?

[comjoe1]

Tried one other test. I removed the low beam relay and jumpered the wires. The lights came on, even with the key in the off position. I hope that helps and means something good.

[Techdude2000]

Checked the fuse. It is good. Dropped the bottom of the right side switch pod. It looks like there are 4 wires going to the start switch, black/white, yellow/orange, brown/red, and blue/white. Turned on the key and checked for power. The only wire that showed power is the black/white one. All others were dead. Where do I look next?

Ok, the relay being jumpered is a normal result, but we already know the relay is good or they wouldn’t work in reverse. Take your voltmeter and make sure you have power on the fuse as well. The lack of power on the brown/red wire at the switch is a problem. Did you have the key on? If so, then we need to look under the right side fairing pocket to see if there’s an issue with the connector that the brown/red wire runs through. It runs through C18, (large blue one at the rear of the white holder frame) on its way from the fuse and up to the switch. Before digging into the pocket area, pull out the headlight adjuster relay and probe for power on the same brown/red wire in its socket. If it’s missing there, then check under the pocket for C18 and find the same wire there and probe for power as well.

[comjoe1]

Yep, key was on. and I do have power to the fuse when the key is on. I even checked both sides by pulling the fuse part way out, just to be sure the fuse was conducting the power. Doesn't hurt to be sure.

Checked the headlight adjuster relay. Brown/red had power when the key was on. I removed the right side pocket and found C18 and the wire. They sure didn't make it easy to get at that. That's when the battery went dead. Should have known that was coming. It is on the charger right now. Probably time to call it quits for the night anyway. Got some family stuff to do. Thanks for your help and attention today. If you have any suggestions for when I get back to it I would appreciate it.

[Techdude2000]

Yep, key was on. and I do have power to the fuse when the key is on. I even checked both sides by pulling the fuse part way out, just to be sure the fuse was conducting the power. Doesn't hurt to be sure.

Checked the headlight adjuster relay. Brown/red had power when the key was on. I removed the right side pocket and found C18 and the wire. They sure didn't make it easy to get at that. That's when the battery went dead. Should have known that was coming. It is on the charger right now. Probably time to call it quits for the night anyway. Got some family stuff to do. Thanks for your help and attention today. If you have any suggestions for when I get back to it I would appreciate it.

Ok, so we know the wire isn’t broken from the fuse to the relay socket, hopefully it’s just an issue at C18, because it will be an easy fix if it’s just getting lost by a bad connection there. If it’s a bad splice in the wire where it splits from the fuse run and goes to C18, it’s going to be fun to locate the splice. I’m helping with my daughter’s school work at home tomorrow, but I will check in from time to time to see where you’re at with it.

[comjoe1]

It does seem to be a problem around c18. I can reach in and wiggle the connector and make the low beams come on but as soon as I turn the highs on they go off. I am going to try to get the connector apart to check it out and will let you know what I find.

[Techdude2000]

It does seem to be a problem around c18. I can reach in and wiggle the connector and make the low beams come on but as soon as I turn the highs on they go off. I am going to try to get the connector apart to check it out and will let you know what I find.

Yep, that’s a bad connection. The extra load for the high beam relay coil is enough to cause a voltage drop across the bad connection at C18 and they all die from a lack of voltage for either relay coil. It’s probably oxidation on the pins of C18. There’s a tab on the side of it that you push in to separate the two halves. It’s tight and tough to do with the shelter in place. Good luck, keep us posted.

[comjoe1]

I took things apart, even took the shelter most of the way off. I can put my hands on the connector but I can't get it apart. There is a button on the bottom and I am pushing it but I can't pull the connector apart. Bedtime now, back at it after work tomorrow.

[Techdude2000]

I took things apart, even took the shelter most of the way off. I can put my hands on the connector but I can't get it apart. There is a button on the bottom and I am pushing it but I can't pull the connector apart. Bedtime now, back at it after work tomorrow.

Yep, it’s a beast to separate. I wish Honda had used a better quality, weather proof connector instead of these cheaper, non weather proof connectors that are a bear to separate. It will come apart, you might have to get it out of the white frame first to get a good grip on it.

[comjoe1]

Finally got it apart. It looks like the connection has been bad for a while and got hot. The female brass receiver is burned off. I need to get it out of the connector and find one like it to replace it. I know they don't cost much but I have to find one that will fit.

[Techdude2000]

Finally got it apart. It looks like the connection has been bad for a while and got hot. The female brass receiver is burned off. I need to get it out of the connector and find one like it to replace it. I know they don't cost much but I have to find one that will fit.

Ok, if you can’t locate a new female pin, then a simple jumper around the connector will do. I know these connectors are Sumitomo, but the exact one is elusive when you search online for it. If you end up doing a jumper, I would just cut off the wire on both sides, bypassing the connector with a good twisted and soldered joint. Are any of the surrounding pins affected or is it isolated to just that pin?

[comjoe1]

Yeah, I thought about the bypass too. It is only that pin involved so that would work. I am going to make a quick attempt to find the pin. If I can't find one that is what I am going to do. I will make sure I get a good, solid connection. I don't really want to take this apart again. Thanks for all of your help. I would not have found it without you.

[Techdude2000]

Yeah, I thought about the bypass too. It is only that pin involved so that would work. I am going to make a quick attempt to find the pin. If I can't find one that is what I am going to do. I will make sure I get a good, solid connection. I don't really want to take this apart again. Thanks for all of your help. I would not have found it without you.

You’re welcome, I’m just glad you didn’t have to dig into any harness bundles to track down a bad splice. Those are way too much fun!

[Av8r1ab]

Another good idea is to waterproof that connector (and others while you're at it). Whether you have just fixed this problem or not, prevention is worth thousands of miles.