Weird Electrical Problem with 3 of 4 Tail Lights...
 

OK so I thought this problem could be fixed with a simple change of a fuse: not the case.

The problem:

My 2005 Honda Civic LX's tail lights are malfunctioning. There are four taillights on my car. One on the left and right side of the car (each share the housing with the turn signals and brake lights). The brake light bulbs serve double duty as brake lights and taillights.

The other two taillights are on the trunk itself and seem to be synced with the license plate lights.

I've provided a rudimentary diagram of my taillights from the vantage point of the rear end, facing the lights directly:

T1 T2 T3 T4
[O] [X] [X] [X]

The "Ts" signify the taillights. The [O] indicates the working taillight and the [X] indicates non-functioning/malfunctioning taillight.

T1 and T4 work as brake and taillights and share the same bulb. T1 works perfectly. T4 only works as a brake light and ceases to work as a taillight.

T2 and T3 are only taillights, and are located on the trunk door. T2 & T3 do not work when the trunk is closed (nor do the license plate lights). However, when I raise the trunk about halfway T2, T3, and the plate lights flicker on and off, and eventually stay on when the trunk is fully raised.

I have already changed the #2 fuse (15 A) for the "small light" (as listed in my owners manual). None of the other fuse names seem to correspond with what I would interpret as taillights. So I am at a loss with the fuses.

I don't want to change the bulbs because they seem to work, kinda. Any suggestions or help would be appreciated.

I am worried this is a more deep seeded problem with the electronic system. Anyway, thanks in advance.

Re: Weird Electrical Problem with 3 of 4 Tail Lights...
 

sounds to me like it's a loose/possibly partially severed wire in the bundle of wires going to the trunk lid. You may need to do a little bit of digging to trace the issue. Since your license plate lights don't work, that leads me to believe that it's in the wire bundle going into the trunk. Probably got pinched somewhere and the movement of the wires reconnects them when you go to open the trunk

If T2 and T3 "work" when the trunk lid is open, then the fuse should still be in tact. Pull the bulb for T4. Since it works as a brake light and not as a tail light, there's a chance that the second filament in the bulb is done.

Re: Weird Electrical Problem with 3 of 4 Tail Lights...
 

The harness has a broken wire in the area near the hinge where it flexes.

Swap the bulb first, use the one on the other side that you know works.
That should tell you if the first bulb is bad or not.

Re: Weird Electrical Problem with 3 of 4 Tail Lights...
 

Here's the bulletin on fixing the harness,

clickypoo

http://ww2.justanswer.com/uploads/thebesthonda/2010-05-26_155036_A08-094.pdf

Re: Weird Electrical Problem with 3 of 4 Tail Lights...
 

xRiCeBoYx and ezone, thank you very much for your helpful responses and expertise.

I did change the break light/taillight blub (T4). (Thank you all for humoring me with my "T" diagram.) The T4 light now works perfectly.

Also I think I've located where the harness may be pinched. I didn't really have time to tinker with it too much though.

I will post my progress as I go. Thanks again for the advice. Electrical stuff is completely foreign to me. This will be a new endeavor.

Re: Weird Electrical Problem with 3 of 4 Tail Lights...
 

The bulletin linked earlier shows exactly where you will find the broken wire, and how to fix it.

Just follow the bouncing ball and sing along, it's really pretty easy.

Re: Weird Electrical Problem with 3 of 4 Tail Lights...
 

I can't encourage people enough to get a multimeter for electrical stuff. You can get one for $10 and up. They take all of the guess work out of electrical/electronics. I've had mine for years and used it for everything from household to automotive electronics. Best purchase you'll ever make. :)

Re: Weird Electrical Problem with 3 of 4 Tail Lights...
 

Your use of TX actually made it easy to help you out. Easier to type than "right outer tail light" because I'm inherently lazy. Lol :_beer:

Re: Weird Electrical Problem with 3 of 4 Tail Lights...
 

If you remove the tape and open up the black plastic loom near front edge of trunk then find the RED/YLW wire and tug on it you will quickly see the problem. Not pinched but broken loose at large crimp connector.

Have a single strand 6" length of wire handy and splice it into broken end, then connect other end forward near crimp terminal.