Rear light - I hate electrics even more than the last guy

[Anonymous]

Ok, here we go again.
I fitted new brake shoes in the rear drum of my '82 GS750TZ and adjusted the brake light switch. At this point, the rear light worked and the brake light came on when I pressed the brake pedal. The brake light didn't come on when I pulled the brake lever but then it never has done since I've had the bike. Feeling very pleased with myself about changing the brake shoes, I thought it was about time I investigated. I took the stop switch apart. A little copper bottomed thing fell out. I put it back in. Something sparked. After this, the only electrical thing that worked was the headlight. Horn, turn signals,dashboard lights rear light and brake light were all dead. I changed the top fuse. Everything started working again except the rear light. I tried putting a single filament bulb in the back. Still, only the brake light works - the rear light won't come on. I replaced the bulb with a new twin filament bulb - same result.
What on earth have I done this time?
The good news is I have a volt meter. The bad news is that the only thing I know how to do with it is measure across the terminals of a battery. Everything else is a mystery.
If any of you knows all about electrics and can speak fluent idiot, then I'd love to hear from you.

Roger

[robinjo]

Roger don't dispair...I'm the first guy who hated electricity and the guys were very helpfull so my bike is up and running again, I'm sure they can do the same for you, I'm sure of it :P

[Anonymous]

Roger, regarding the front brake light switch; are you sure you found all the pieces? There is a piece that fits into the brake lever, and moves the copper piece that you found. Also check all the contacts for cleanliness. It sounds as though you shorted something during reinstallation.

As for the voltmeter, just find a good ground (earth) and you can check the voltage available at any accessible point (like the taillight socket). If you have a multimeter, you can check continuity with the ohms function. Just make sure that there is no current in the system, and check for conductivity between any two points. That will indicate whether you have a good circuit, or a break, corrosion, or non-functiong switch. If you have a circuit where you should not, then you have an unwanted ground or short circuit.

If you check at your local library, you can probably get an instruction book on basic electrical testing. Some people have been lucky enough to find a shop manual for their bikes also.

Good luck,

[SqDancerLynn1]

First I would check the brake light switch to see if there is 12v on the orange/green wire? I don't have dia for GS750. If the 12v is missing you need to work back towards the battery. You may have blown more than one fuse. The top fuse i believe is the main fuse, the one below that? is for the light circuit? and is tied into the same 12 battery supply of the main fuse, pull them out and check them with your meter. Set the meter to Rx1 on the ohms scale you should read 0-1 ohms depending on accuracy of the meter

[earlfor]

Re: Rear light - I hate electrics even more than the last gu

On your front brake light switch, the G/R wire is common to the front and rear brake light switch, so if your rear switch works, then this wire is OK. The G/R wire is powered by the 15 amp fuse holder in your fuse box. (there is only one 15 amp fuse holder)
The white wire from the front brake light switch goes directly to the tail light bulb with only a bullet connector to connect.
By your saying the rear light does not now work, I understand you to mean that now your front brake light DOES work, but you tail light does NOT. Your tail light is fed directly off the "ON" quadrant of your ignition switch with a solid brown wire. The tail light is grounded into a double connector with a black/white wire. That connector also serves to ground the rear turn signals. Do your rear turn signals work? If they do, then the tail light ground is likely OK. If all of these things check out, then I would suspect the
bulb socket in the tail light assembly. Also, check for corroded connectors or hard or brittle wires.

A tip for installing front brake light switches. Since the parts are so small and difficult to hold in place, I loosen the clamping bolts on the front brake mount (make sure the fluid cap is on tightly) and rotate the assembly upside down. Then you can see what youre doing, and just drop the parts in exactly where they need to be and screw the brake switch cap back on. Easy ..... :-) OH....
dont forget to rotate the brake to right side up. (its too difficult to use with the lever on the inside of the handlebars :-) )

Earl

Ok, here we go again.
I fitted new brake shoes in the rear drum of my '82 GS750TZ and adjusted the brake light switch. At this point, the rear light worked and the brake light came on when I pressed the brake pedal. The brake light didn't come on when I pulled the brake lever but then it nev
er has done since I've had the bike. Feeling very pleased with myself about changing the brake shoes, I thought it was about time I investigated. I took the stop switch apart. A little copper bottomed thing fell out. I put it back in. Something sparked. After this, the only electrical thing that worked was the headlight. Horn, turn signals,dashboard lights rear light and brake light were all dead. I changed the top fuse. Everything started working again except the rear light. I tried putting a single filament bulb in the back. Still, only the brake light works - the rear light won't come on. I replaced the bulb with a new twin filament bulb - same result.
What on earth have I done this time?
The good news is I have a volt meter. The bad news is that the only thing I know how to do with it is measure across the terminals of a battery. Everything else is a mystery.
If any of you knows all about electrics and can speak fluent idiot, then I'd love to hear from you.

Roger