GL1000 headlight problem

Note that the Clymer wiring diagram for all 1000's is incorrect for the starter switch. The physical pin layout is wrong with regards to "FREE" and "PRESS". Problems should arise if trying to diagnose and R&R a switch from this manual for either early or late model 1000's.

I'll go through what I had to do to my '78 to get the switch back in action. Skim from what I've done for your particular needs.

Pictures are left to right.

'75-'77 Clymer diagram
'78-'79 Clymer diagram
My '78

Remove the switch from the housing. This can be done on the bike at the handlebar. Remove the two bottom screws to open the housing up.
Remove the screw for the cable securing clamp inside the housing. Remove the screw for the start switch.
Twist the upper housing out of the way for access to the lower housing that contains the switch and remove the switch from the housing.

Once the switch is free from the housing you can disassemble the switch. It is serviceable.

A small screwdriver (or even your fingers) will remove the lower plate that secures the pushbutton. Four locking tabs hold it into the plastic switch housing. Popping one side of the lower plate gives access to the pushbutton for removal.

**Careful** there are two springs attached to the pushbutton. One to return the pushbutton to the out position and another for the pin contact.

Pictures show the disassembled parts.
Note that the plastic housing where the pins for each wire has deformed particular to the headlight wire. It has had enough current pass through the pin to heat it sufficiently to warp the top edge and not allow the slider pin to make contact. This problem has progressively gotten worse on this bike. Also, the slider pin does not extend as it should to make positive contact with the wired pins. It is spring-loaded and should pop upward when not in the plastic housing.

Disassembly of the pushbutton.
The slider pin itself has deformed the plastic it slides in.
The plastic casing is no longer square to the slider pin and must be squared-up again. I use a utility knife to remove any deformed plastic and then correct the bend on the slider pin.
I also replace the slider pins spring with that from a BIC pen cut-to-length in the photo's.
I screw the spring into the recess allowed for the original spring and then trim the spring to a length that has the slider external from the plastic housing. Orientation of the slider is provided by slots molded into the plastic. Once installed back into the plastic housing and in operation I am certain of positive contact with the wired pins.

Next I backcut the plastic around the headlight pin to relief the contact pad so that the slider makes positive contact within the switch housing once reassembled.
I use a utility knife to do this.

Once partially assembled I then polish the contact surfaces using a Dremel with a straight plastic bristle brush and rubbing compound.
This technique takes only a couple seconds per contact. I use a solvent when done to clean the contact surfaces. I then use dielectric grease on each contact pin and the the exterior surfaces of the plastic pushbutton housing. Assembled, everything slides smoothly and contact is positive.

Test the switch for operation and, if it passes, reassemble the start switch into the handlebar housing.

...and the front brake light switch as well.
Same basic operation; two contact pins and a slider pin.
Notice one of the contact pins has a hole worn through it? It's been pushed a lot of times in 35 years..
The slider pin can be rotated on the plastic for a fresher area of metal. There are depressions where the two contact pins have been sliding over the wired pins for many years. Rotating the cylindrical pin on the plastic gives the other two wired pins a more positive contact surface.
Cleaned all with the Dremel, rubbing compound and solvent process as above. Used the ignition grease as well.