LED Turn Signal Polarity Switch

Hello Forum! This is my first post on this forum but I frequent and moderate a few so I'm well versed in how these forums work.

I have a 1998 Ford Escort Wagon. I bought a set of 3157 wedge base switchback LED's(Amber/White) to use as turn signals.So as not to cut into the factory loom I bought a set of wired step downs to mitigate the hyper flash. The SBLED's use reversing the polarity to activate each color. I have a VERY basic knowledge of electronics so as far as what I think I need to do I'm thinking a SPDT relay spliced in before the step downs would do the trick but I'm not sure how to wire the configuration on the actual relay. The extension step down loom uses three wires, Black/Red/White. I assume they are ground/power/neutral in order. Can someone give instruction on how I can complete this circuit so that it switches the polarity of the incoming current to enable both colors to energize. Right now with the just the extension step down loom Amber lights when the turn signal is activated. No hyperflash so the step downs seem to be doing their job.

A few other questions....

I mounted the step down transformers to the back side of the radiator in the air path to cool them down. Is this advisable or do they need to operate at a higher temperature i.e., should I place them outside the airflow path?

Will installing the SPDT relays interfere with the OEM flasher modules? I ask because as far as I understand it the OEM flasher module sends out a particular current value pulse. Won't that interfere with the relay operation?

I searched the forum and was able to put together some bits and pieces but nothing really directly related to what I want to do.

John

John,

If you are using these lamps as front turn signals, they need to be amber to be legal in US. Why do you want to be able to switch them to white? Is the switching to be triggered by a manual switch or by an electrical signal?

You can mount the load resistors in any location that permits a bit of air exchange - mounting in an airstream is not necessary.

Do you have a link to the supplier webpage for the LEDs?

I want to set it up so that the white portion stays on as a running light when the headlights are turned on but changes to amber once the turn signal switch is activated. In this state it will switch from white to amber and back. Once I return the stem to its off position the white will remain as it was. The switching will be triggered by the OEM turn signal stem. With the headlights off during the daytime only the amber will energize when I trigger it with the stem.

My limited knowledge tells me an SPDT on each loom will do the trick but, again, I'm not that knowledgeable about how that would be configured beyond that.

I have pictures but don't have enough posts to be able to display them which would probably make explaining what I'm trying to do a little easier.

John

The 3 wire "step down device" should be all you need for your application. There is no polarity reversal involved in this installation.
"Usually" the RD wire is tied to the +12V driving the headlights and causes the LED colour to be white.
The WH wire is connected to the +12V driving the turn signal circuit.
BK is ground.

You can test the functionality by connecting the leads to a 12V battery.

What do the instructions for this product suggest?

The Switchback LED's came from Superbrightleds. They work by switching from one color to the next by reversing the polarity. Without the relay the circuit works as follows. With headlights off the SB is off until I turn on the turn signal. When I turn on the turn signal it lights amber then goes from off completely to amber. No white light.

What I've been told by Superbright is I need to install a relay that will reverse the polarity if I want the white portion of the led's to light. Apparently SB's are for car turn signal systems that work on this type of system. The system I have on my car apparently works by regulating the voltage from medium bright/running light to high bright/turn signal on and pulsing it. As I mentioned, I'd like to light the white portion of the SB as a running light and the amber portion for the turn signal pulse. I'm told a relay can do this but I need to know how to wire the loom to the relay for it to do this.

John

Are you wanting the light to be white when your headlights are in daytime running light mode and also in full brightness mode?
When you want to signal a turn are you wanting the light to be:
1. Amber - White - Amber - White
2. Amber - Off- Amber - Off

The easiest would be to just get something like this which does what you need without external circuitry.

https://www.amazon.ca/AUXITO-Extremely-Chipsets-Switchback-Projector/dp/B0756B3T1D/ref=sr_1_5?crid=203LJ6VJN8HPO&keywords=3157+switchback+led&qid=1569162195&sprefix=3157+%2Caps%2C391&sr=8-5

Link doesn't work.

John

novanutcase wrote:

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Link doesn't work.

John

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Here is a screenshot of a product that simplify your installation issue.