Try changing both bulbs...
cause the bulbs are burned out? cause the fuse is blown? jeez....
Blown fuse? Damaged buss board?
probably the fuse is blown.
Most likely a blown fuse
Tail lights are usually on the same fuse with interior lights and dash lights. That is so you will know when the fuse is blown. Brake lights are usually on a different circuit. If a fuse is blown, try to figure out the cause rather than just replacing the fuse.
Blown fuses. Consult your owners' manual for their location.
be cause your bulb is blown out
A blown fuse can cause the dashlights and taillights to stop working on a 2001 Dodge 1500.
Blown fuse or defective brake light switch.
There are several things that can cause your 2000 Cadillac dashboard lights to quit working. The most common cause is a blown fuse.
If a Passat 04 TDI's indicator lights are not working, check the fuse. A blown fuse can cause the lights to stop working.
Most likely cause would be a blown fuse.