Triumphrat

rmak

I've been gradually cleaning and making operational all of the switches and lights on my new T140E. The last real big hurtle is the brake lights. They worked lousy when I got the bike, coming on whenever they wanted to.

When I test with an ohm meter I get a reading through the foot pedal from the white to the two browns and can break the circuit when I push on the pedal. I also have power through a test light from white or brown to a ground unless I push the pedal, then I just get a light through the white to ground.

On the grip switch, I do not have a reading with an ohm meter through the switch, but have power to ground from both white and brown?? This power to ground check works for both sides regardless if the switch is off or engaged unless I push the brake pedal then the brown goes dead.

I can make an ohm check connection from the grip brown to the pedal brown. However, I cannot make any connection in any way to the wire at the end for the tail/stop light from either switch . No wire to ground light regardless if I push the pedal, squeeze the grip or not. Nothing at the tailight end.

If you are confused, sorry, but that's how I feel. I know the brake light is screwy because you have to break the connection in the switches to make a circuit for the light. Or so I do believe.

The white I believe to be fine since that's the power and everything has power except the tail light. The brown looks good visually everywhere except where I can't see because of black tape.

Bad switch? Broken wire? Electrical dummy? One, two or all? Help and thanks.

thirdbike

Don't know what you are attempting to do by using an ohm meter. All it really will do is measure if there is a path between the leads which could be short, a light bulb element or whatever.
Use a voltmeter or test light. You should always have power on the white wire to ground with the ignition on. You should have power on the brown wire, as well, when the brake light switch is engaged. Follow the circuit from source through to the stop lamp until you do not have power and you will find the fault. The front brake switch is a real fuss pot.

epynt1050

Assuming you have a negative earth T140E (some early US versions I believe were positive earth) the the white wire should be at 12+volts with the ignition on. The two stop light switches are simply on/off "normally open" switches in parallel. When either brake is activated the contacts in the switch closes effectively connecting the white wire to the outgoing brown wire. These two brown wires lead to one side of the brake light bulb. The other side of the brake light bulb is connected to earth via a black wire.
When either of the brakes is activated the closure of the switch causes the brown wire to go to 12v and hence the bulb has 12v on one terminal and earth (0v) at the other terminal. Bulb will light.
Easiest way to check the circuit is to disconnect the white and brown wires at each brake switch and with the ignition on, just touch each pair of white and brown wires together in turn. With the wires together the brake light should come on.
If this does not happen, the you have a fault in the circuit other than at the switch.
Once happy with the rest of the circuit reconnect the wires to the switches and try again. Failure of the bulb to light will indicate a faulty switch.

rmak

Thanks guys for the help. Much appreciated. It's positive earth. Why I always get the weird stuff, I'll never know. Here's what I found out.

Someone had tightened the adjustment for the rear brake switch so that it was bottoming out making it connected in it's normal state. When the pedal was pushed down the switch button went to where it's supposed to go so the power went off. I guess the switch was giving someone trouble, so they thought tightening it would fix it. It didn't.

I finally realized that the little button that separated the contacts on the front switch had little to do with it making a circuit except that it kept it apart until the lever adjusting screw pushed the contacts together. That was a "duhh" moment for me, but who engineered this stuff anyhow!! Usually when there's a button on a switch it's to activate.

I still have a bad wire somewhere between the rear switch and the tail light, but all switches are operating correctly now. I may just run a new wire around for the tail light since the brown is all taped up, unless someone has a better idea. Thanks again!