They don't light up.
Check the fuses first. Your owner's manual should tell you where they are. Most likely its the fuse. If not, check the bulbs because on some vehicles a bad bulb may break the entire circuit. They are separate circuits, separate fuses and separate swithes. Check the fuse and the tail light bulbs.
The way to tell if a fox tail palm is truly dead is to check the stem and roots. If both are mushy and brittle, the plant is dead.
Sure: you don't have a complete electrical circuit to working bulbs. Are the bulbs good? Fuse? Have you checked the ground wire at the taillights? Often on older vehicles the ground connection becomes rusted and the lights will stop working. Have you verified that voltage is present in the tail light wire? Sometimes a faulty connection somewhere between the switch and the tail lights will cause the lights to fail. Have you verified that the headlight switch is functioning properly? While Brake lights are controlled by the brake light switch (part of the brake pedal) and the turn signal switch, tail lights are controlled by the headlight switch. Track down which part isn't working right and then you'll know. BTW, I THINK the tail lights are on the same fuse circuit as the dash lights.
If a switch is added, all of the bulbs/lights/motors can be turned on and off at the same time, instead of needing several switches. Also, if a bulb is dead, you can't tell what bulb is dead because they are all connected.
If you do not have working tail lights on your GMC vehicle it may be an issue with the wiring or your lights may be burned out.
If a switch is added, all of the bulbs/lights/motors can be turned on and off at the same time, instead of needing several switches. Also, if a bulb is dead, you can't tell what bulb is dead because they are all connected.
change the headlight switch it controls the running lights....$15 at autozone
On the back of a car there are tail lights, turn signals, and brake lights. Cars also have back up lights that tell people when the car is in reverse.
Check the fuses first. If the fuses are ok check the reverse switch. The switch is under the dash on some models, and on the transmission on others. A bad or misaligned switch is the most likely cause for no back up lights.
One of the bulbs burned out. That's the obvious reason for them not working. Look in your owners manual for the location on your rear tail light fuse. Either under the drivers side dash or under the hood.
Check the package, it will tell you if it can be used for these bulbs. Be careful of compact florescent.
Front or rear, turn signal or reverse lights,dome light or dash? Most bulbs are stamped on them what they are. Most autoparts stores can tell you in about 2 minutes. good luck