QuestionWhen I step on the footbrake the brake light goes on, but when using the hand brake, there is no light, wondering where to look for a short in the wiring or just a loose wire, would that also affect the horn not working? Rode the bike last year, horn and brake light both worked when we first bought it 2 yrs ago. Thanks so much.
AnswerI don't know your level of electrical knowledge, so here are a couple of important definitions (in case you don't already know):
Open circuit - (infinite ohms) - The same ohm meter reading you get when the meter leads aren't connected to anything. No current can flow through an open circuit.
Short circuit - (zero ohms) - The same ohm meter reading you get when the meter leads are touching each other. A short circuit is literally a shortcut for the electricity. Current always flows through the path of least resistance and a zero ohms is about as low a resistance as you can get.
The problem with the brake light must be in the front brakelight switch or it's circuit. Disconnect the wires from the switch on the master cylinder and connect them together (a short piece of wire will do if you can't get the ends of the connectors to touch). If the brake light comes on when the wires are connected the problem is in the switch - either it needs to be repaced (available through the aftermarket) or adjusted.
If the brakelight doesn't come on when you connect the wires together the problem is in the wiring. Study the schematic in your shop manual and look first for something that isn't plugged in. If everytiing is plugged in you will need to get out your voltmeter and start checking the wires themselves. If you have voltage at one end of a wire and not the other the wire is usually broken (open circuit).
Troubleshooting the problem with the horn will be similar. I would start by checking for voltage at the horn when the button is pressed. If there is voltage but no honk, you probably need to replace the 24 year old original horn. If there is no voltage you need to study the schematic and check the wires.
It could also be a dirty horn button. In fact, I would try that before I started tracing wires. You can usually clean the switches & buttons on the handlebars without taking anything apart. If you look at the bottoms of your switch clusters you will see that there are small holes, just the right size to accept the straw from the contact cleaner and located so that it will spray right onto the contacts.
Just spray the contact cleaner into the hole and work the switch or button vigorously several times, then turn on the key & try it. You might need to repeat the process several times before it works properly.
If you can't get it working after 3 or 4 tries you will need to take it apart.
If you find broken parts you will need to make a trip to the wreckers.
If there is just too much dirt & hardened grease in there for the contact cleaner to wash out you will need to clean it manually. Use an old toothbrush & more contact cleaner.
DO NOT use sandpaper - particles of the grit will become imbedded into the contact's surface and cause all kinds of problems.
If a contact is pitted you can dress it with a POINTS FILE. DO NOT use a regular file. POINTS FILES are designed for dressing ignition points and have the their teeth cut at the proper angle &c so that they will leave a very smooth surface.
If you don't have a shop manual you should get one - your bike is an antique and you will have a hard time finding a shop that will work on it. The sad fact is that a lot of the mechanics working now are too young to remember bikes this old and aren't interested in learning about them so that they can do a proper job since yours may be the only one they see this year. This means that you will have to do most of your own work, and working on a bike without a good shop manual is just not worth the headaches. (My bikes are from the same era - that's why I fix them myself.)
I recommend that you get two manuals - a Factory Shop Manual and a Haynes or Clymer. That way when you don't understand the explanation in one you will probably figure it out when you have read the other too. If you spend some time on Google you might even find a factory manual available for free download.
