The tail light assy is a 3 bulb on a 1996 mustang coupe. Only one light bulb is illuminating in each assy. There appear to be at 2 additional bulbs per assy that are not illuminating. In addition the turn signal blinks fast as if a bulb is out. All bulbs are good as noted when rotated through the working socket, the bulbs work. This is true on both the right and left side of the vehicle.

Will have to replace the bulb. This is done from inside the trunk. Remove carpeted cover and there are twist type sockets in the housing which hold the bulbs. For the dash, you will have to remove the cluster assy and locate the correct bulb, twist and remove socket assy. it is a small bulb in the dash!

Hi Leslie, To answer your questions, 1) a fuse can look undamaged and be open circuit (blown) 2) One bulb being blown should have no effect on the other, but if both are blown, the vehicle will have no tail lights! 3) The bulb holders should have no effect on each other, but if the earthing is bad, which is possible on a vehicle which has any rust, the problem could be related. Take a short length of electrical cable and while holding one end to the outer metal housing of the bulb holder with the rear lights switched on, connect the other end to a good metal earth on the body. If the lights or light works the problem is the earth connection. Regards and happy new year John

usualy there is a faulty earth to the bulb cluster remove them and clean all the conectors spray the harness and cluster with wd40 or similer put all bulbs back in and see if that works but i would go with a bad earth hope this helps ivan uk

Replacing tail/brake/backup lights and turn signal bulbs (coupe)

1. Make sure the headlamp control

is in the OFF position and then

open the hatchback.

2. From inside the luggage

compartment remove the wing nut

of the rear light assembly cover.

3. Using a Phillips screw driver

remove the screw. The lamp is still

retained by a spring loaded clip.

Remove by gently pulling out the

light housing.

4. Turn the bulb socket counterclockwise as far as possible and pull it

out.

5. Pull the bulb straight out of the socket.

Install in reverse order.

Replacing tail/brake/backup lights and turn signal bulbs (sedan)

1. Make sure the headlamp control

is in the OFF position and then

open the trunk.

2. From inside the luggage

compartment remove the three wing

nuts of the light housing.

3. Gently pull the light housing to

the outside.

4. Turn the bulb socket

counterclockwise and pull it out.

5. Pull the bulb straight out of the socket.
Install in reverse order.

Replacing tail/brake/backup lights and turn signal bulbs (wagon)

1. Make sure the headlamp control

is in the OFF position and then

open the hatchback.

2. Using a screw driver remove the

fixings and trim from the body.

3. Remove the socket from the lamp

assembly

4. Pull the bulb straight out of the

socket.
Install in reverse order.


Hope this helps.

Zeppelinx12

It may sound silly, but check your brake light bulbs to see if they have been installed incorrectly. Brake light bulbs have two filaments, one for tail light, and a brighter one for brake lights. On some cars if the bulb is installed wrong, the brighter filament will stay on for tail lights. The only other thing I can think of is the wrong bulbs have been installed.

open tail gate remove 3 either torx or phillips screws remove light assy remove 3 more screws to get circuit board off light assy replace bulb

You have a combination of nuts and screws to remove the taillight assembly.
Type in " e-bay " to your computer and type in the taillight you want, and you will see pictures of them for sale.
I did, and found:
1) 2 screws under/ or alongside the rubber seal that is at the trunk lid opening, and 2) 2 or may be 3 nuts on studs that extend inside the trunk.
Once all these are removed, you will access the bulbs.
God bless your efforts.

I have taken my car to many shops to solve this problem. Long story short your tail light has a bad circut and entire lamp must be replaced. (Lamp cost approximate $130.00)

tail light bulbs are replaced by removing the tail light housings. The housings are accessed by removing the nuts, the nuts are secured behind the inner trunk liner inside the trunk. Remove fasteners holding liner in place, remove 3 nuts for each housing(i believe it's 3 nuts if my memory serves me right), remove housing and replace bulbs

If you pull back the carpet on the side of the trunk, you can reach in and get to the bulbs.