UMich97

Ok, so starting the other day, the outer most light on my drivers side tail light no longer sequences when I turn on the hazards or the turn signal. However, it seems as though it does light up when I apply the brakes (per the girl I asked at the gas station). Anyone have any ideas what would cause this? I have the plug and play set from Webelectric. Would hate to have to spend another $100+ on a new set after just two years.

KdF

If it works with the Brakes, I would say the bulb needs replacement.

SilverSkoundrel

That sounds like the easiest 1st thing to try

UMich97

Thanks guys. I'm thinking that's where I'll start...hopefully, it's that easy.

watchdevil

Makes no sense because the bright or high filament in the bulb is dedicated to both brake lamps and turn signals while the dim filament is for running lamps with the headlamps/parking lamps on at night. If the bulb failed, neither the brake lamp nor turn signal action would light up the bulb at all.

The sequential turn signal modules are designed to delay lighting up the middle and outer taillamp bulb sections during a turn signal flash. If the outer bulb works during the brake lamps then it has to be a defect in the sequential turn signal module for that side of the car. Capacitors in the turn signal module discharge at different rates to complete each bulb circuit during a flash cycle.

UMich97

Thanks man, that's what I was wondering, but wasn't sure on the technical details, thus my post asking for input. Appreciate the detailed insights.

With that said, I had my wife check for me tonight and she said it doesn't light up when I hit the brake. So, either the gal at the gas station was wrong, or it's an intermittent problem.

watchdevil

It's likely just the bulb.

UMich97

That's what I'm guessing now too, since the wife says its out in both situations. Off to the parts store for a new one.

B1GP1MP1N

I figure since the bulbs are turning off and on more often, the life of the bulbs would be decreased with the sequential harnesses. So changing bulbs will probably happen more often.

UMich97

I never thought of that, but it does make sense. I've always heard more energy is used turning a light on/off than leaving it on, so makes sense.

I picked up a bulb today and will install it this weekend.

watchdevil

The bulbs do not turn on and off more often. The bulbs are turned on and off the same number of times sequentially as if they were flashed all at once at the same time.

B1GP1MP1N

Yeah I guess you're right. I guess I'm no Thomas Edison. = ) lol

KdF

So, whilst I was not gonna reply....You are saying that if I am sitting at a stoplight, with my foot on the Brake, the signals do not work??

watchdevil

No that is not what I am saying at all. It's rather difficult to understand any of this if you don't have any automotive electrical knowledge.

Historically for most vehicles, the way combination turn signals and brake lamps work together is controlled by the turn signal switch with it's multiple contacts inside.

When there is no turn signal activated while the brakes are applied, current is passed from the brake lamp switch to the turn signal switch where the current is distributed to the left and right taillamps resulting in brake lamps lit on both sides.

When a turn signal is activated (either left or right), the current from the brake lamp switch is deactivated by the turn signal switch only from the flashing side while current passing through a flasher unit is directed by the turn signal switch to the taillamp that needs to be flashed.

On newer Mustangs, the Smart Junction Box manages distribution and operation of lighting using voltage signals it receives from switches which are processed to switch on the voltage outputs that each lamp receives.

D'prived

I bought my sequentials (plug & play) from WebElectric and they came with a lifetime warranty.

UMich97

Hmm, I'll have to look for my paperwork if swapping the bulb doesn't work. Unfortunately, didn't have a chance to do it this past weekend.

UMich97

Well, didn't get to swapping the bulb yet, with the holiday weekend and all. However, when I was leaving Starbucks tonight and hit the unlock button, I noticed that all of the tail lights illuminate. It's only when I hit the brake or turn signal that the outer most bulb doesn't light up. Anyone know if it could still be the bulb...or more likely the wiring?

watchdevil

You have to remember there are two filaments in every taillamp bulb. That means two circuits. One illuminates the dim filament used for parking lamps, sidemarkers and rear running lamps. The bright filament is for operation of the brake lamps and turn signals.

When you activate the unlock feature on your remote, it only illuminates the dim parking lamp/running lamp circuit. When you lock the vehicle with the remote, it flashes the bright filaments in each bulb that operate with the turn signal/brake lamps.

So yes when you unlock the vehicle all three bulbs on each side will illuminate because the dim filament within the bulb in question is still functional. It is the bright filament in that same bulb that is blown not allowing it to illuminate when you lock the doors with the remote, nor will it illuminate during braking or turn signal activation.

I have been doing this kind of work for a living for 30 years, so replace the bulb already and your problem should go away!

UMich97

Thanks watchdevil...guess I just need to make it a priority and get it done already. I've got the bulb sitting in the garage, just need about 10-15 minutes to pull the housing.