Rear signal lights out, bulbs good

Both rear signal lights are out, so are brake lights. Driving lights work, so are high beam lights and all front turn signal lights. What should I check? I have done some research, but I could not locate the fuse or the relay flasher for my 2004 Malibu Maxx. Appreciate any help here.

Your taillights work, if I understand your post. Turn on the head lights and have someone observe the tail lights. Step on the brakes and if the tail lights go out, then you have a broken ground wire.

See if the emergency flashers work in the rear and if the middle brake light works ok also. The brake lights and turn signals run through the emergency flasher unit. Cycling the flashers switch a few times may help fix the trouble.

Replace the bulbs, and go from there. Keep it simple.

How do I find and fix the broken ground wire? Neither the emergency flashers work in the rear, nor the middle brake light works, although the emergency flashers work in the front. The bulbs work in the rear when I turn on the engine and parked. However, when I drive at night, all the lights in the back is dark.
Thank you very much for all the reply.

I don’t understand. The lights in the rear come on when the headlight switch is off? and goes off when the headlight switch is on? The taillights work during the day but not at night?

Engine running, headlight switch off
Taillights on or off?

Engine running, headlight switch on park position
taillights on/off?

Engine running, headlight switch on headlight position, brakes off
taillights on/off?

Engine running, headlight switch on headlight position, brakes on
taillights on/off?
brake lights on/off?

BTW, the fuses and the headlight relay should be in a fuse box under the hood, usually near the battery.

My car has auto lighting. When I have engine off, but radio on, the tail lights are on. When I turn the engine on, the tail lights are still on. When I press down the brake pedal, braking lights are off. Braking lights are always off. I.e. regardless engine on/off, headlights on/off, braking lights are off. I suspect that the taillights are out when I am driving b/c people give me the high-beam signal at night lately and it is always dark behind me when there is no other cars behind me.

Thanks a million.

Since you say that the brake lights are out, does the cruise control work? The cruise control is deactivated when you press the brake pedal. If your cruise control isn’t working, you may want to check the brake light switch.

I will try the cruise control after work. What if the cruise control is working? It has been a detective work lately on finding the cause of the darkness behind my car. Appreciated your help.

Triedaq, the cruise control isn’t working. How do I check the brake light switch? Thanks.

I haven’t dealt with a brake light switch for 50 years when I replaced the switch on my 1947 Pontiac. This switch was on the master cylinder. However, I think more modern cars the switch is under the dashboard, clips on, is activated by the brake pedal lever. I think you can unplug a connector from the switch. If this is the case, unplug the connector and using a multimeter, set it on the D.C. voltage scale. With the negative lead of the multimeter connected to a chassis ground, insert the postive lead into one of the sockets on the connector. With the ignition switch on, see if the multitester indicates a voltage. If it doesn’t, put the lead into the other socket. If you are not getting voltage to the brake switch, the problem is before the switch. A fuse may be blown. If you do get voltage, set the multitester on the ohm scale. The ohm should be infinite. Press the pedal and the ohms should be zero. If this isn’t the case, the brake light switch is defective.
Perhaps someone more knowledgeable than I am can advise.

Thanks Triedaq. I have an update on the cruise control. After few tries this morning, I could get the cruise control on and pressed the brake, the cruise control is off. The cruise control doesn’t get on easily as before. I have to try it for few times before I get it. Does this change your diagnostic of the brake light switch? Thank you very much.

If the cruise control goes off when you step on the brake, the switch is apparently working. I think you need to find a shop that specializes in electrical work.

Thanks. I will find a shop. Thank you, Triedaq.

This is one main criticism I have of GM. They have figured out how to build a reliable simple car. My 2002 Saturn SL has been one of the most reliable cars I have ever had. But in most of their models, they put in too much automatic junk. I guess they think that all their customers are so moronic that they can’t even turn on the headlights or the windshield wipers for themselves.

This is where they have almost all their problems. So much for my rant. In the old days, the brake lights were pretty simple. You have some wire that connects the battery to the fuse, the fuse to the brake light switch and the brake light switch to the bulbs. It was either a bulb, the fuse or the switch, and occasionally a broken wire.

Now you have a computer involved. I’m not sure if it uses the body control module to make this a Rube Goldberg affair or it they use a separate DLR module with the automatic light sensor. But in either case, the center brake light was supposed to bypass the computer or anything else so that it at least would light up. Since it doesn’t, I suspect that you have a blown fuse that you are not aware of or a broken wire.

Without the wiring diagrams for your specific vehicle, I’m afraid we can’t help much. Sometimes you get lucky and someone here owns a similar vehicle and has the factory service manuals, but most of the time it doesn’t happen that way.

Thank you all for responding this post. It turned out that the bulbs were bad. They had two filaments, one for driving light and one for braking light. the driving filament was good, but the braking filament burnt out. I spent $5 on the bulbs and $5 on labor to fix it. The high mount braking light is still not working, but I could drive at night now. I was told that there are two filaments, but I didn’t know what filament was. Now I learned something more than I had anticipated. I will report what happens to the high mount light when I get it figured out/fixed. Thanks.

Oh, when the bulbs are out, the blinker flashes way too fast. Next time, it will be the clue to replace bulbs.

The bulbs in the middle brake light are most likely bad and will need to replace them also.

Yahoo Waterboy rules 3rd post nails it again. KISS Keep It Simple Stupid, though nowhere did I see the blinker blinking fast until the end.