DIY sequential blinkers 2005 Ford Mustang


Joined Mar 14, 2008
Thanks for the design if possible could you adjust for the change in voltage the range being 12-15vdc @ 1amp?
The circuit will operate at up to 17V.

To drive the 1A bulbs you can add an N-MOSFET at each output for the second and third bulbs (the blinker drives the first light directly).
Just about any N-MOSFET with an on-resistance of <1Ω will work.

Do you need all bulbs to come on for the emergency flasher?
Having both sides sequence for the emergency may be acceptable as it would better get your attention.

Where would you buy your parts?

Thread Starter


Joined Aug 23, 2017
I think having both sets cycle for hazard lights would look good however form follows function I typically get all my components from digi key, I work at radio shack and get a good deal through them


Joined Nov 18, 2016
Pretty much what we need is output signal shape, amplitude, frequency, duty cycles if any and the same for the input signal, we will make the formula.
You have to take into account:
Third brake light
Side markers. Side markers as turn.
Dual filament bulbs.
Bulbs with orange envelopes.

Effect on bulb monitoring systems
OEM operation vs new operation if different.
The use of Amber bulbs.

I don't know much about it so I won't even cover it. There may be fog lights to consider.

In older vehicles a lot of the switching was in the steering column. In 2000, one car put a lot of complexity in the dash mounted hazard switch. Now it's BCM all the way baby.

There are cars that alternately flash the side lights. The wrap around lenses have eliminated side markers.

Don't forget flasher load.


Joined Sep 30, 2009
In older vehicles a lot of the switching was in the steering column. In 2000, one car put a lot of complexity in the dash mounted hazard switch.
I found that out when replacing the turn switch in a 2000 Chevy S10. was the first 'modern' switch I replaced. Didn't even need to pull the steering wheel like the old days.
Yea. The Symptom "intermittent turn signals". Temporary fix: Bump Hazard switch. Perm Fix: Replace Hazard switch Took me a while to figure it out.

Now there would be the air bag nonsense. Back in the day it was easy to pull a steering wheel. I pulled aa 1968 Chrysler and 1965 Ford. I replaced the rack and pinion on an 1982 Toyota.


Joined Jan 15, 2015
Fond memories of a 68 Mercury Cougar with the motorized system. It is amazing what today's automotive electrical systems are. If I were to try replacing a sequential turn signal system today I believe many of the considerations mentioned in this thread would be a priority. I would likely lean towards using a uC based system simply because while sequentially running three or four turn signal lamps is not complicated with a discreet component circuit there are considerations such as does braking or hazard flasher lights figure in? Recently helped a friend install a LED show system on his motorcycle. One nice feature was a brake light input so anytime the brake line goes high all tricolor LEDs go red. The nice thing about using a uC based controller is the availability of digital inputs for decision making in the code.

If a single filament bulb is all that is used and it only functions as a turn signal then things are simple but if dual filament bulbs are used and a filament has more than a single purpose things can get a bit complicated. Even looking at the old wiring diagrams for the late 60s cars which used the motorized switch the wiring was a nightmare trying to follow it. Even today's motorcycles use a engine control unit and a on board computer. My old '92 motorcycle has a complete control unit for all the lights including the turn signals which time out with distance.

Anyway, if I were looking to replace or recreate the old sequential turn signals I would likely opt for using a uC for control for the reasons I mentioned. Not at all to say using discreet components is a bad approach or idea depending on the complexity of the lamp circuits.


Thread Starter


Joined Aug 23, 2017
Sorry for the delay I've just uploaded a video where I put my cars' tail lights in every possible state in order to make a truth table, however note the mid light and reverse lights only activate when braking or reversing respectively. Also note that hazard lights take precedence over blinker signals and there is no alternate flash pattern associated with those combinations. Also I noticed that only the outside four lights are dual filament.
Thanks again everyone



Joined Mar 14, 2008
So do you want the inside lights to blink also?
If so, then you will need to deal with a single filament bulb doing double-duty.

Thread Starter


Joined Aug 23, 2017
In theory I could just replace the insides with a dual filament and use the output from mosfets normally while maintaining my original headlamp switches ability to power running lights correct?