[Ksmith353_98]

I just bought a 07 TRX400. It was missing the taillight. I installed a new one. Question is with the headlight switch off should the head lights be coming on with the brake lights? With the tail light disconnected the head lights do not come on with the brakes. With the head lights on everything works as expected. Before I spend hours tracing out wires I wanted to know if that's how its susposed to work.

 

[XplicitRacing6]

Just to clarify, your saying that when you press the brakes your head lights come on?

 

[Ksmith353_98]

CORRECT, that ain't right is it.

 

[Ksmith353_98]

After testing I thought the green and brown wires at the taillight were reversed, cut them switched them turned out I was wrong. Next attempt is to replace headlight bulbs, it has some LEDs one is burnt out or hardly working.

 

[Z7What]

You need to download the manual for your bike and start testing wires. Dont throw parts at it hoping to find your problem. Find the problem then fix the issue. Are you sure your turning the correct headlight switch? One is on/off and the other is low/high.

You said when your headlight switch is OFF and you have the taillight is hooked up, that when you press the brakes, the headlights turn on? Does the taillight work as it should, dim with headlights on and brighter when brakes are press? Does this happen when you hit each of the 3 brake levers one by one or does it only happen when you hit only one of them. If so, which one?

It sounds to me that you taillight and brake light wires may be touching so whenever you press the brake it backfeeds into the taillight circuit causing the lights to come on.

Wayne

 

[Goober]

I’m thinking the PO miswired something? Before you installed the new TL Did the headlights come on when you tapped the brake?
Are the front LED lights a mod by you or the PO?

 

[Ksmith353_98]

Headlight operation was normal before installing the tail light.

Per the wiring diagram there is a common ground between the taillight, brake switches, and headlights, I'm starting to think it's in the tail light itself.

When testing the wiring harness with a multimeter I'm getting proper results.

 

[misterclean59]

A bad ground can do funny things like this. If the brake light has a bad ground It will find one, even if it is thru the head light bulb.

 

[Z7What]

If you use some spare wire and hook the TL up to a 12v battery doesn it work correctly?

You should be able to ohm the grounds to see if thats a issue.

Wayne

 

[Ksmith353_98]

To Ohm the ground would I put my black probe on the battery black, and the red on the tail light ground?

 

[Melatv]

To Ohm the ground would I put my black probe on the battery black, and the red on the tail light ground?

If you are referring to the green wire on the connector -- it should read zero from battery to green wire. How many wires are on the light you are using? The Br wire is the tail light and the G/Y wire is the Brake light.

 

[Ksmith353_98]

SOLVED. As expected the LED headlight bulbs were the fault. I swapped to a standard bulb problem solved. So the LED bulbs must have had a cross connection somehow. The PO didn't have a tail light installed so they never noticed the problem.

 

[Z7What]

SOLVED. As expected the LED headlight bulbs were the fault. I swapped to a standard bulb problem solved. So the LED bulbs must have had a cross connection somehow. The PO didn't have a tail light installed so they never noticed the problem.

Take your ohm meter and put one lead on one wire of the tailight and the other lead on the other wire. Does the meter beep or give you a reading? Will the light work if you just hook it up directly to a battery?

Wayne

 

[SamUK]

Haven’t read replies so excuse me if you get a repeat answer, bad ground, Chinese tail light or possibly cheap (Chinese) bulbs. Had similar issues myself in the past.