Headlights ON, Brake Lights always ON, Headlights Off Brake Lights Work Properly
 

Hello Guys,

I just bought this car as my first ever Honda and I'm already getting tired of the car and looking to maybe sell it.

But I would still like to give it a chance and fix it. I have search the forums and also Google and nothing as the wording is hard to statement.

The Car: 2003 Honda Civic Si (Manuel)

Problem:

About 2 weeks ago my left back brake light stopped working. Thinking it was the bulb I replaced it, but yet it still didn't work. As it was a 2 pack and tried the other buld but no resolve. So I returned the bulbs but the new set did nothing. So I took the same bulbs and put it on the right side. Magic Nothing wrong with the bulbs, just the left side will not light.

So I left it, but now this is the major issue:
1. During the day with Daylights on the Dash board blinks everytime I push on the brakes. At the back of the car the brake lights work the way they should, but the left side still doesn't light. Also to note is that the front marking lights also blink when I push the brakes.

2. At night when I turn the headlights on it doesn't matter then as ALL the lights are on in the dash and also all the brake lights are on.

3. With this effect I have also loss my cruise control but knowing crusie controls if I fix whatever is causing this massive dangerious issue the crusie would come back.

I have tested all the fuses and they are good, the turn lights work also

Any help that you guys can offer me would be greatly appreciated.

Thanks

The brake lights and taillights share a common black ground wire in the rear hatch/trunk area. I think this common ground wire is broken or disconnected. Also look for an additional broken/damaged power or ground wire for left brake light.

Thanks I will try that. Do you have a scymatic of anything.

I agree, you've lost the ground in the back. Take one of the bulb sockets out and measure the voltage from the shell of the bulb (which should be grounded) to actual ground with the brake lights on (prop something heavy against the brake pedal to keep them on). It should be much less than 1 volt. Follow that wire to where it grounds.

If it's a hatch, the wires tend to break where they go across between the body and hatch. They flex there every time the hatch is opened.