MustangHowTo Sequential Tail Light Install

Sequential Tail Light Installation

Always ensure the vehicle you are working under is supported securely with jack stands, wear appropriate clothing and safety goggles. Be weary of your clothing and the proximity to moving parts. If you are uncomfortable about attempting an installation, DON'T......Seek a qualified service person or facility to help with your installation. This articles contained in this site are in addition to and enhancement of existing OEM specified procedures and practices. With regard to specifications and procedures, the OEM manual, procedure or practice shall dictate and govern.

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In a stock Mustang, only the outer two lamps function as brake/turn signal/tail light lamps. The inside lamp (closest to the center of the car) only functions as a tail light. Fortunately, for the 1996-2004 automobiles, the inside lamp socket that comes with the car is set up to accept an additional lamp connector, and it already contains a dual filament lamp.

The STS-1M kit comes with pig-tail wire connectors that will convert the inside sockets to function as a brake/turn signal/tail light, just like the other sockets. This connector reduces installation time, and allows you to keep the Ford Factory sockets.

Some people experience flasher problems after they install the STS modules. There is an electronic flasher module in the car that runs the turn signals and hazard lamps. This module has a function that warns the driver when a lamp burns out by flashing at about twice the normal flash rate. Since the STS system separates the rear lamps in order to sequence them, the electronic flasher thinks that one of the bulbs is burned out, so it flashes quickly. When this happens, the sequencer modules don't have enough time to light all the lamps.

The STS-1M kit includes a flasher that has been modified to handle this feature. In addition, the flash rate is reduced to allow more time for the full lighting of all lamps.

Follow the instructions on the next few pages, and in no time, you will be driving a car that not only looks better, but is now safer because it is getting more attention by the drivers behind you.

Right Side

1) Remove the plastic nuts that hold the trunk liner. Pull the liner back to expose the nuts that hold the fixture in place. Using an 11mm socket, remove the nuts that hold the fixture. Carefully remove the grommet that holds the harness in the car body. Remove the tail light fixture from the car and take it to a work bench. Place a soft cloth on the bench in order to protect the lens. The picture below shows a fixture that has been removed from a car.

2) Remove the inside lamp socket (the one circled in the picture above). Slide the gasket out of the socket and off the wires. With an awl or other pointed tool, pierce a small hole in the gasket.

3) Note that there are markings on the socket, and there is no wire in the MAJOR position. Remove the lamp and insert the supplied wire connector into this position. It's a tight fit, so use a needle nose pliers and be sure that it's fully seated. SPECIAL NOTE: There may be some plastic flash or other crud in the hole. Make sure that it's clear or you will have trouble getting the pigtail in far enough to make contact. After installation, if the middle lamp does not light, this is very likely the problem.

4) Install the gasket onto the wires and slide it back into the socket. If the lamp you removed is a dual filament lamp, then put the lamp back into the socket. Otherwise, obtain a #3157 lamp and install it into this socket.

5) Remove the middle socket from the tail light fixture. Insert the inside socket into the middle position, and insert the middle socket into the inside position. There is room for this swap, but since each car is different, you might have to unwrap some of the harness tape, and/or pull a clip out of the car body.

6) Locate the harness inside the trunk. There is a small section of the harness between the grommet and the connector. Carefully remove the wrap to expose the individual wires, and make the following connections:

A) Using a quick-splice, connect the RED module wire to the turn signal wire. On the Right side of the car, the signal wire is orange with a blue stripe. On the Left side of the car, the signal wire is green with an orange stripe. (There may be two signal wires in the harness. You can make the connection to either one.)

B) Using a quick-splice, connect the BLACK module wire to the black harness wire (this is ground).

7) Using the same pointed tool you used to put a hole in the socket gasket, punch two holes through the grommet. Use some wax or silicone spray to help the tool penetrate the grommet. Feed the BLUE and WHITE module wires through the holes you made and run the wires out towards the tail light fixture. (TIP: If you have trouble getting the wires through the holes, you can cut the stripped end off, since you will be trimming the wires anyway.)

C) Trim the WHITE module wire to length and strip about 1/2" of insulation. Using a wire nut, connect it to the new pigtail of the middle socket (this is the old inside socket that you moved to the middle position).

D) Cut the signal wire (orange with blue stripe) of the outside socket about 3-4" from the socket. Strip 1/2" of insulation from the signal wire coming from the outside socket. Trim the BLUE module wire to length and strip about 1/2" of insulation. Using a wire nut, connect it to the signal wire that goes to the socket.

E) Cap off the short harness wire with a wire nut and use some tie wraps to bundle the wires to the harness. This will reduce the chance of pinching a wire against the body of the car.

8) For the Left Side of the car, repeat the above steps using the other sequencer module. Note that the colors of the car wiring are different on this side of the car. The MAJOR wire on the Left Side is green with an orange stripe.

9) Using an 8mm socket, remove the knee bolster cover and the knee bolster. Locate the turn signal flasher in your car. On the '96-'98 models, the flasher is located to the rear of the fuse panel. On the '99-'03 cars, the flasher is under the dash, to the left of the radio. To remove the flasher, use a small screwdriver to release the clip that holds it to the bracket. Then disconnect the plug from the flasher. Replace the yellow flasher module with the modified unit supplied with the STS kit.

Testing

Insert the harness back into the car -- module first, then the plug. Re-connect the plug. Before remounting the fixtures, turn on the hazard flashers and check to see that the lamps sequence from the inside of the car to the outside. If something isn't working, double check your wiring for errors.

Point the wire nuts up to keep water from collecting in them, then remount the fixtures. When re-mounting the fixtures into the car, be careful not to pinch any of the wires on the frame or mounting studs. This can cause a short that will destroy the module!

Use the supplied tie wraps or some electrical tape to neaten up the wires and to hold the modules to the wiring harness. If you use a tie wrap to hold the modules to the harness, leave the tie wrap very loose. DO NOT OVER TIGHTEN THEM. If you damage the cover, the unit may not function properly or moisture may enter the system and slowly destroy it.