I was recently pulled over when a cop noticed that my back lights would go out when I stepped on the brakes. I replaced the bulbs in back and that helped for like a month. Now I have absolutely no running lights in the back, although the brake lights come on when I brake. Does anyone know what this is from or how to fix it? Thank you for the help.

 

What year of car?

Do the front and side running lights work (if the car has these), is it just the back tail lights? Are all the taillights out including the ones on the trunk lid (if the car has these)?

 

It is a 1989 Camry. It is all of the taillights that are out as well as the right side light. The license plate light works andboth rear turn signals both work. The little light on the left side works also. Thanks.

 

Does this car have a light failure sensor system? If so you should be a warning light on the dash. You may be able to view this when you first turn on the ign key and all the warning lights turn on.

All of these lights come off the same circuit through the TAIL fuse. The rear left and right side lights come off the same wiring, thus if one side is working and the other not would suggest a bulb or wiring problem.

The rear tail lights go through a Light Failure Sensor. This sensor can go bad causing problems such as your but not completely sure this is the problem given the right side light is also out. This light does not receive power from the sensor.

I suggest to start digging into the trunk and finding the wiring to lights. Then start checking for power at each wire. Buy a cheap voltmeter (try Harbor Freight if in your area) or hook up a 12V lamp to 2 wires and use this. Connect one wire of the lamb to the circuit under test and the other to ground.

If the light comes on there is power in the circuit (of course turn on the running lights first).

Taillight wiring should be GREEN in color for power wires going to the bulb or Light Failure Sensor and WHITE/BLACK for wires coming from the bulb and then going to ground. You want to test for power between the green wire and ground.

The sensor should located in the trunk, drivers side behind a panel (I think). Have never seen one but folks state it may be yellow in color. Check for power at the green wire (again with running lights on). If a bad sensor it will need to be replaced or just bypassed.

Suspect though the car has a wiring issue, thus start checking the wiring for loose or broken connections. And find the sensor and check for power at the GREEN wire.

 

I found the yellow box, exactly where you said, the wires are all intact. I will have to get a voltage meter to check the green one. Is it easy to bypass if that is what the problem is? Thanks for all of your help, I really appreciate it.

 

Use a voltmeter or a 12V bulb with 2 wires.

Not too bad on bypassing the sensor IF this is the problem. Again it may be a wiring issue as one side light is also out, this light does not run through the sensor.

Also check the bulb connectors for corrosion. The fuse is OK as the license and other side light bulbs work.

With ign switch, brake lights and parking/head lights OFF (or disconnect battery), cut the Green and Blue/Green-stripe wires and splice them together.

Cut the Green/White stripe and Green/Red stripe wires and connect them together.

The Yellow wire has 12v DC when the ign switch on, thus cut it and apply electrical tape or something else to prevent it from shorting to the chassis.

The Yellow/Green stripe wire goes to the lamp indicator out bulb on the dash, cut and tape this also.

If the sensor is the problem, the dealer should sell them but very costly. Most people find them at auto junk yards, etc. Or just leave the sensor disconnected, it will not hurt anything by doing so.

If you happen to blow the fuse by mistake, it is the 15A TAIL fuse.

 

Thank you for all of the info and help!

 

Glad to help.

Post back when you find something out.

 

Revitalizing an old thread but having a similar issue. Taillights are dim, stepping on the brake makes them worse but right side brake light seems ok. Left side goes out. Center brake light is ok. i suspect a ground issue but cannot find the ground point. Manual says it is on the left deck. My meter quit in the middle of this last night so i didn't get the readings i wanted.

 

Year of car?