Trench - 2010 TE250 low brakelight voltage?

[R_Little]

My brake light stopped working.
Taillight still works.
Brake light on these bikes only illuminates when the motor is running.
I removed the taillight to find the middle yellow wire busted off just before where the taillight plugs in.
I snipped the wires and reinserted the 3 wires back in the connector.
I Put it back together and still no taillight.
When bike is running and brake switch tripped my meter shows only 7.1V to the LED brake light. The taillight is getting 13.3V. I presume 7V is insufficient to illuminate the LEDs.

What is the correct voltage to the brake light? 12V, no?

The connections I repaired seem to be fine.

Thanks

 

[Trenchcoat85]

(LEDs are current driven, and typically red ones drop about 1.8v across 'em so it's hard to say what voltage is required. betcha you can take a 9v transistor radio battery and test your tail and brake lights though- independent of the bikes electrical system. Polarity counts with LEDs remember.... "diode")

Hi rich-

sounds like your hydraulically actuated brake light switch has bad contacts. check first with the above test to ensure both brake and tail lights function (i'm thinking they do, a lot of LED taillights use the same LEDS for both. don't know about husky tho). you can just jumper a wire from your bike battery to each wire (not the ground) if you don't have a 9v handy.

btw, is this for the front brake lever AND the rear brake pedal? The front brake uses a N/C micro switch, the rear pedal uses the N/O hydraulically activated switch.

lmk what you find out.

I do not run with a rear pedal-activated light; I like to have the choice of braking without that ultra-bright brake light telling cops i'm slowing down. Only my front lever activates the brake light. Inspections? just plug the wire back in. Cali doesn't do annual inspections anymore.

 

[R_Little]

My rear switch wires were ripped off at the connector.

i will check it out.

maybe I can short the rear switch to check.

 

[R_Little]

It was the front brake microswitch.

Do you know where I can find one?

 

[Trenchcoat85]

It was the front brake microswitch.

Do you know where I can find one?

bet'cha ktm or anybody else using brembo brakes has 'em. IOW, if a bike has brake lights and uses the brembo brake lever with the "wing" in front of the pivot (which turns the brake light off) the switch will be the same- but you may hafta adapt your wiring. BTW, I'm guessing if you unplug the front switch, the back brake pedal will activate the light normally.

husky part #8000A0929 https://www.ktm-parts.com/8000A0929.html $26.47 (SWM/Sherco it's about twice as much but the same part number) The newer models have the switch and wiring together. The other part number I quoted earlier was just the harness.

looks like the ktm number is 50311050100 and hovers around $50 (!wow!).

 

[R_Little]

The rear switch wires ripped off at the connector years ago.
I fixed the rear wiring with a couple of those blue butt connectors. Is that blue covering on the butt connector a a shrink wrap if I hit it with a heat gun. I hope so, otherwise it might just rip off again.

When activated the rear switch has "0" resistance and the brake light works. The front has a few ohms. Does that account for the voltage drop to 7V at the brake light?

I wonder if i can clean the front switch? The wiring is good.

 

[Trenchcoat85]

The rear switch wires ripped off at the connector years ago.
I fixed the rear wiring with a couple of those blue butt connectors. Is that blue covering on the butt connector a a shrink wrap if I hit it with a heat gun. I hope so, otherwise it might just rip off again.

When activated the rear switch has "0" resistance and the brake light works. The front has a few ohms. Does that account for the voltage drop to 7V at the brake light?

I wonder if i can clean the front switch? The wiring is good.

The front switch is making minor contact it seems (hands-off-the-lever holds the switch open). The switch itself may be bad or the "button" worn/broken or one of your plastic mounting tabs might be broken or out of its socket. The switch just pops out of the lever perch (gently). Use a small screwdriver.

Unplug the front switch to see what your voltage situation is with the rear brake on & off.

The micro switch is sealed fairly well but there is no harm at all in trying wd-40 on the little button itself; clean the wiring harness contacts with it also.

The blue plastic on your butt connectors is just insulation and maybe a tiny amount of strain relief for wire bends. wiring itself should really never be under tension. the rear brake wire should be on the engine side of the frame and not exposed to brush etc.

I've already said it, but really you only need one brake that activates the light.

 

[R_Little]

I pulled the butt connectors and soldered the wire with dual shrink wrap.
I ride tight woods and sticks do get inside the frame rails, that's how the original connector ripped off.
Anyway, i zip tied it tight and will simply cut the wire if I ever need to replace the hydraulic switch.

The front switch is mounted tight and the wires are good. It clicks positive when I pull the lever. Must be dirt or corrosion in there somehow. I'll spray some WD and see what happens.

As you say one switch is sufficient.

Thanks