78 Gl1000 Lighting Problems


Information and questions on GL1000 Goldwings (1975-1979)
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coleman
Posts: 13
Joined: Fri Sep 22, 2017 1:40 am
Location: Los Angeles, California
Motorcycle: 1978 GL1000

78 Gl1000 Lighting Problems

Post by coleman » Thu Dec 07, 2017 4:01 pm



Hi Guys,

So I've been trying to get the taillight working on my '78 Gl1000 to no avail. The instrument lighting doesn't work either. I'm going to run you all through my observations and what I've found in case it clicks with anyone.

The light works when the bike is in Park. It's an LED tail light that came with the bike. It has turn signals built in which I was able to get working by piggybacking them into the same plug as the actual blinkers, so I know the light works and such. Been meaning to try cleaning the ignition switch to see if that solves it. The starter button was all dirty when I bought it and I couldn't get the starter to spin until I took it apart and cleaned. Part of the brake light should be on at all times while the bike is running right? and then the other part of it lights up when I apply the brakes? Any suggestions of where to start? I'm familiar with the diagram and will continue going through it with a continuity tester, but if anyone has some ideas short of that I'd like to hear them.

Potentially unrelated, but as soon as I turn the ignition to on, the accessory fuse blows.

None of the instrument lighting works (e.g. speedometer, tachometer, fuel gauge, oil temp gauge, voltage gauge). The red oil indicator, nuetral light, Hi beam indicator, left and right blinker indicators work. I checked a couple of the light bulbs in the cluster on top of the false tank, I think fuel level and oil temp, and the lights bulbs were fine (or at least they provided resistance). I traced the wires leading into the cluster checking voltage. 12 v into the regulator, 7 volts coming out like it should be.

When I tested the light bulb housing, I noticed something strange. It appears that both of the contacts leading to the bulb are negative (ground?). What I mean by this is that when I touch the test leads on my multimeter to either lead, the only way it reads with the correct voltage is when I touch the other lead to the positive side of the battery. I'm new to all of this so I could be wrong, but shouldn't one of them be the positve one where I touch the test lead to it and the other lead to the negative side of the battery to get it to read with the correct voltage?

Another problem that has started recently is that the headlight low running light no longer turns on when the bike is on. The headlight still works when I put it on high, but no running light when it's on low.

The brake light is the most concerning to me since it's plain unsafe, but I'd like to figure all of them out. After I fix the lighting, I just have to fix.... like 15 other things but at least I can ride it :D



SnoBrdr
Posts: 512
Joined: Fri Mar 07, 2014 9:01 am
Location: Providence, Rhode Island
Motorcycle: 1978 GL 1000

129K Original Owner

Re: 78 Gl1000 Lighting Problems

Post by SnoBrdr » Thu Dec 07, 2017 6:59 pm

coleman wrote:
Thu Dec 07, 2017 4:01 pm
Hi Guys,

So I've been trying to get the taillight working on my '78 Gl1000 to no avail. The instrument lighting doesn't work either. I'm going to run you all through my observations and what I've found in case it clicks with anyone.

The light works when the bike is in Park. It's an LED tail light that came with the bike. It has turn signals built in which I was able to get working by piggybacking them into the same plug as the actual blinkers, so I know the light works and such. Been meaning to try cleaning the ignition switch to see if that solves it. The starter button was all dirty when I bought it and I couldn't get the starter to spin until I took it apart and cleaned. Part of the brake light should be on at all times while the bike is running right? and then the other part of it lights up when I apply the brakes? Any suggestions of where to start? I'm familiar with the diagram and will continue going through it with a continuity tester, but if anyone has some ideas short of that I'd like to hear them.

Potentially unrelated, but as soon as I turn the ignition to on, the accessory fuse blows.

None of the instrument lighting works (e.g. speedometer, tachometer, fuel gauge, oil temp gauge, voltage gauge). The red oil indicator, nuetral light, Hi beam indicator, left and right blinker indicators work. I checked a couple of the light bulbs in the cluster on top of the false tank, I think fuel level and oil temp, and the lights bulbs were fine (or at least they provided resistance). I traced the wires leading into the cluster checking voltage. 12 v into the regulator, 7 volts coming out like it should be.

When I tested the light bulb housing, I noticed something strange. It appears that both of the contacts leading to the bulb are negative (ground?). What I mean by this is that when I touch the test leads on my multimeter to either lead, the only way it reads with the correct voltage is when I touch the other lead to the positive side of the battery. I'm new to all of this so I could be wrong, but shouldn't one of them be the positve one where I touch the test lead to it and the other lead to the negative side of the battery to get it to read with the correct voltage?

Another problem that has started recently is that the headlight low running light no longer turns on when the bike is on. The headlight still works when I put it on high, but no running light when it's on low.

The brake light is the most concerning to me since it's plain unsafe, but I'd like to figure all of them out. After I fix the lighting, I just have to fix.... like 15 other things but at least I can ride it :D
Did this have a faring on it at one time?

If so they could have butchered up the wires hidden behind the head light.

They used to use 3M Scotch Locks and they worked OK till you tried to remove them.

If this is so, you could have a lot of cut or grounded out or even disconnected wires.

coleman
Posts: 13
Joined: Fri Sep 22, 2017 1:40 am
Location: Los Angeles, California
Motorcycle: 1978 GL1000

Re: 78 Gl1000 Lighting Problems

Post by coleman » Sun Dec 10, 2017 6:01 pm

How can I tell if it used to have a fairing? I’ve discovered a lot of shotty maintenance that was done to it a few owners back so it wouldn’t surprise me if they mucked up the wiring. Supposedly the tail lights worked before I bought it though so I’m hoping it’ll be something easier.

SnoBrdr
Posts: 512
Joined: Fri Mar 07, 2014 9:01 am
Location: Providence, Rhode Island
Motorcycle: 1978 GL 1000

129K Original Owner

Re: 78 Gl1000 Lighting Problems

Post by SnoBrdr » Sun Dec 10, 2017 7:05 pm

coleman wrote:
Sun Dec 10, 2017 6:01 pm
How can I tell if it used to have a fairing? I’ve discovered a lot of shotty maintenance that was done to it a few owners back so it wouldn’t surprise me if they mucked up the wiring. Supposedly the tail lights worked before I bought it though so I’m hoping it’ll be something easier.
You should grab yourself both a manual and a wiring diagram.

One of the easiest ways to see if there was a faring is to check your false tank.

Are all the parts still connected to it so that it can drop down, including the stay wire.

Usually they are all gone if it had a faring.

I'd venture to say that 90% of all the 70s GL had farings at one time, if not more.

fatalbert
Posts: 2
Joined: Sat Aug 12, 2017 11:11 am
Location: seattle,wash,usa
Motorcycle: 1975 honda goldwing

Re: 78 Gl1000 Lighting Problems

Post by fatalbert » Sun Dec 10, 2017 10:40 pm

You really need a schematic to troubleshoot electrical issues. On your bike, the tail light wire colored dark green is the common ground for both the break and running light.

The brown wire for the tail light bulb is for the parking/running light and the voltage is sourced from the fuse panel (brown wire) and should be labeled parking for the fuse.

The green/yellow wire from the tail light bulb gets its 12v source by activating either brake. When the brake switch is closed, it looks like the voltage source is from the green/white wire on the fuse panel listed as turn signal/horn. Check the brake switch for continuity through the switch with the ohm meter to make sure it is working.

To troubleshoot the blown fuse, there is obviously a dead short or the fuse in it is too small for the current. Use the ohm meter and look between the fuse contacts and chassis ground. Disconnect the battery ground when using the ohm function of the meter.

Get a manual with a schematic. The Clymers has a pretty easy to follow schematic. Solve one problem at a time. Many time when you fix one wiring issue it fixes multiple problems. Good luck. Al

fatalbert
Posts: 2
Joined: Sat Aug 12, 2017 11:11 am
Location: seattle,wash,usa
Motorcycle: 1975 honda goldwing

Re: 78 Gl1000 Lighting Problems

Post by fatalbert » Sun Dec 10, 2017 10:48 pm

There are some useful manuals and electrical schematics on its sight under "manuals" that will help you.

coleman
Posts: 13
Joined: Fri Sep 22, 2017 1:40 am
Location: Los Angeles, California
Motorcycle: 1978 GL1000

Re: 78 Gl1000 Lighting Problems

Post by coleman » Thu Dec 14, 2017 8:58 pm

Already downloaded everything on this site and bound it with the binding machine at work so I've got me a pretty useful shop manual. If the Clymers manual is better than the colored wiring diagram on this site and the wiring diagram from the manual, I'll definitely purchase one.

When using the ohmmeter on the fuses, how do I know what the correct resistance should be? Do I only have to disconnect the battery ground when testing resistance or should I also be disconnecting when I test for voltage?

All the components are still attached to the false tank, so I don't know if it had a fairing. Whoever owned it a few owners back did some shotty maintenance so it wouldn't surprise me if they messed up the wiring. For reference, they closed off the weep hole with some black putty-like stuff to stop an oil leak :roll:

I guess I'll just have to get back going through the diagram testing things out. I was hoping that this combination of symptoms might click for someone who experienced before and that there'd be an easy fix.

For the brake light, can anyone think of a little temporary fix I could rig up while I figure it out? Just something to provide a running light and maybe link up the rear brake switch?

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DenverWinger
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Location: Denver, CO
Motorcycle: 1972 CL-350 (1980-1988) sold
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1980 GL-1100 STD Vetter (2005-)
1993 GL-1500A Aspencade (2017-)
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Re: 78 Gl1000 Lighting Problems

Post by DenverWinger » Fri Dec 15, 2017 1:15 am

Temporary brake light hookup: In-line fuse holder with 5 amp fuse from + of battery connected to one terminal of rear brake light switch, other terminal of brake light switch connected to Brake filament of tail light bulb. This will light the brake light when you step on the pedal regardless of ignition switch.

Have you pulled off the seat to see if there's any damage to the wiring going to the rear lights? Not much wiring on a GL1000, it should be easy to trace....

If you are testing a fuse with an ohmmeter, a good fuse will show near zero ohms, a bad fuse will give you no reading at all if it is removed from its circuit.


They say 98% of all Hardleys ever made are still on the road..... The other 2% made it home. :lol:
(I stole this from somebody on another GW site...) :roll:

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