T350 Electrical problem.

spike · Post by **spike** » Fri Jun 19, 2009 1:54 am

Despite the fact that we are now really feeling the sting now, I'm trying to finish a few projects and trying to get em finished without spending too much. New saddle, wheels are ready to go back, forks are getting sorted out on the cheap, motor runs, new sprockets and chain… almost ready for the DOT inspection.

So my T350 is almost done, but I've stumbled into a new prob. When I switch the bike on, my rear brake light lights up. It's not the switch, you can unplug it and the light stays on. I've also tried a different switch (known to be good) and it changes nothing.
If I switch to the Parking position, the rear light, not the brake light switches on, but the brake light doesn't work.
The electrical wiring is untouched. All standard US version (ex-USAF pilot). All switches and other lights, flashers parts etc. work fine.

I'm starting to think my main switch is gettin funky. with the help of the diagram, could one of you knowledgeable type tell me what to look for before I splash money on a new switch or key for a switch?

Thanks in advance.

White = Blanc
Brown = Brun
Black = Noir

tz375 · Post by **tz375** » Fri Jun 19, 2009 7:10 am

The main switch sounds as if it's OK.

The brake light comes on when power is applied via the brake light switch. Poer comes from the main switch to the brake switch to the lamp and then to ground. So I would start by pulling the rear brake light out of circuit and confirm that it's teh problem.

Then I would flush it with WD40 and move the center pin and and out a few times to see if that frees it up. If the switch tests out OK with a multimeter after that, then adjust it. If not, throw it away. That switch is pretty generic and a switch from almost any bike made in the last century will probably work, so there are lots of cheap switches available.

advant63 · Post by **advant63** » Fri Jun 19, 2009 9:06 am

spike, is it possible that you have mixed the white wire of the ignition coil and the white wire of the brake light? the white wire of the brake is connected to the orange wire somewhere.

Suzukidave · Post by **Suzukidave** » Fri Jun 19, 2009 10:25 am

Or the front brake switch could be the problem

spike · Post by **spike** » Fri Jun 19, 2009 11:05 pm

Thanks for the insight… I am really peed off with electrickery… because I know it should be logical and I ain't

Trouble is deffo with the white and orange wires going to the rear light.
It is the brake light that's on when it should be off. The rear pilot does its job when it should (night riding and parking position).

White and orange show continuity when tested. Brake switch is Ok. Main switch is OK (found another one with a key and it behaves like the other one).

It's as if current was bypassing the switch. The switch works but it's as if it was overridden? Will have a look at the front brake switch… we never had these fitted standard here, but since it is a US bike, it could be fitted. If it's stuck on all the time, it could well be the prob.

I have the front wheel off at the moment… wait and see.

tz375 · Post by **tz375** » Sat Jun 20, 2009 8:47 am

Start with both light switches. Disconnect the white lead from each in turn and see if the brake light goes out.

If the brake light is still on when both switches are disconnected, then follow the white lead back from the tail light and see where it goes.

Remember that the white lead should only have power when the switch is ON, so if you get your multi meter and connect it between the frame and the white lead at the switch, there should be 12v when you apply the brakes and zero when the brakes are off. Disconnect the white lead coming out of the switch for that test.

If there is 12v on the white lead (at the switch with the lead disconnected) then the switch is permanently ON and needs to be cleaned or replaced.

spike · Post by **spike** » Mon Jun 22, 2009 4:44 am

I AM DUMB

It's official now.

I had the front wheel off and the lever was sagging ie switch on

All the Smaller Ts were sold without front brake switch here… so it didn't strike me that I had an extra brake switch somewhere… DUH

johnakay · Post by **johnakay** » Mon Jun 22, 2009 5:49 am

spike wrote:I AM DUMB It's official now.

I had the front wheel off and the lever was sagging ie switch on

All the Smaller Ts were sold without front brake switch here… so it didn't strike me that I had an extra brake switch somewhere… DUH

oh we've all done that but maybe not in that order.
I've got several ''T'shirt and I wear them with pride

H2RICK · Post by **H2RICK** » Mon Jun 22, 2009 8:45 am

Yes, spike, as John says we've all been caught by little things like that at one time or another.
I once had a T250 to work on that was eating batteries....slowly. Charging system was great with excellent output. Battery was new and I made sure it was fully charged before beginning the troubleshooting investigation. Nothing mysterious was found in the shop so I thought I'd take it for a ride with one of the other guys following me in case it died on the road. After 5 minutes, he pulled up beside me at a stop sign and asked me why I was riding the brakes. "Riding the brakes ?? No I wouldn't do anything dopey like that. These flippin' 250's are slow enough without making 'em worse."
He told me my brake light was on the whole time. Turns out the rear brake light switch was slightly out of adjustment and I never noticed it in the shop.
This was enough to slowwwwwly drain the battery while riding around town.