Diode Dynamics Switchbacks and BCM / Tail Light Issues

[300mag]

@Grimmer , I think I need to do this, at times I'm noticing a hyper flash from the opt7 signals, it seems to go away if the turn the headlights. just trying to make sure I understand your diagram. on the anode side of the diodes, one diode taps into center parking lamp wire, other diode taps Into switched power (pin 3 of headlight connector, do u know wire color! by chance) pair together cathode ends of the diodes and cut green wire of opt7 harness and connect diode to opt7 side of green wire. did I get it correct?

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[Grimmer]

Yes, that's correct.

If I had to do it again, I would take the green wire on the OPT7 side of the connector and cut it. Then add female blade terminals on both sides of the cut. Using the etrailer diodes, connect the "car side" of the cut green wire to the side of the etrailer diode that has two male blade terminals (either one). And connect the OPT7 side of the cut green wire to side of the etrailer diode that has a single male blade terminal. Then connect the purple drop wire from the diode dynamics DRL add-on harness to the remaining male blade terminal on the side of the etrailer diode pack that has two connectors.

That way there will be no modification to any of the car's factory wiring.

Repeat for the other side of the car.

If you are planning to skip the $40 Diode Dynamics harness, I can look up the factory headlight harness wire color.

Edit:
The wire with the switched (hot in start or run) power in the connector on the back of the headlamp is "GY-VT" (GreY with a VioleT stripe). The diagram is for the 2016 Mustang without headlamp leveling. That same circuit exists from the fuse block with the same color wire for the cars with headlamp leveling, but it goes to a different connector (headlamp control module). In reality, any switched power (with adequate size/power) should work here. The headlamp circuit was just a nearby convenience, especially since Diode Dynamics offers their DRL add-on harness.

I've never even heard of headlamp leveling, it appears that the cars that have it should have 4 positions marked on the bottom of the headlamp switch dial and you can push in the center of the headlamp switch (or maybe pull out the ring?) Anyway, the headlamp leveling was likely not an option in the USA (just guessing since I never had the choice to add it). If you do have it, then we can look at the other connectors if you want.

 

[300mag]

Yes, that's correct.

If I had to do it again, I would take the green wire on the OPT7 side of the connector and cut it. Then add female blade terminals on both sides of the cut. Using the etrailer diodes, connect the "car side" of the cut green wire to the side of the etrailer diode that has two male blade terminals (either one). And connect the OPT7 side of the cut green wire to side of the etrailer diode that has a single male blade terminal. Then connect the purple drop wire from the diode dynamics DRL add-on harness to the remaining male blade terminal on the side of the etrailer diode pack that has two connectors.

That way there will be no modification to any of the car's factory wiring.

Repeat for the other side of the car.

If you are planning to skip the $40 Diode Dynamics harness, I can look up the factory headlight harness wire color.

Edit:
The wire with the switched (hot in start or run) power in the connector on the back of the headlamp is "GY-VT" (GreY with a VioleT stripe). The diagram is for the 2016 Mustang without headlamp leveling. That same circuit exists from the fuse block with the same color wire for the cars with headlamp leveling, but it goes to a different connector (headlamp control module). In reality, any switched power (with adequate size/power) should work here. The headlamp circuit was just a nearby convenience, especially since Diode Dynamics offers their DRL add-on harness.

I've never even heard of headlamp leveling, it appears that the cars that have it should have 4 positions marked on the bottom of the headlamp switch dial and you can push in the center of the headlamp switch (or maybe pull out the ring?) Anyway, the headlamp leveling was likely not an option in the USA (just guessing since I never had the choice to add it). If you do have it, then we can look at the other connectors if you want.

Thanks very much appreciated for the headlight connector wire color as I won't be using the DD harness, I think I got it now, without being in front of the car wiring it's hard for me to make sense in my head.

on a side note I emailed opt7 about the hyper flashing and there response was recheck install or else use the attached prepaid label to return for refund(not even replacement) , as it is a known issue and they can't do anything about it.

 

[Grimmer]

I should have taken more pictures during the various stages of installation...

It will make more sense once you are looking at it. The key is to interrupt the original electrical flow from the parking light circuit into the OPT7 LED and force it to go through the diode, which is a "one-way valve" for electricity. (i.e. cut the green wire and install the diode inline with it...otherwise the switched power from the headlamp will power up the entire parking light circuit. This is cosmetically undesirable and puts the load of all parking lights onto that wire.

The second diode does the same thing for the switched headlamp circuit. It protects the parking light circuit from powering the switched headlight signal circuit CBB68. This is important to keep the load of CBB68 off the parking light circuit (which is switched directly by the BdyCM, not a relay). (EDIT: this may not be entirely correct. The wiring diagram does not indicate a relay in the circuit, but the pin description on the BCM panel includes the word "relay", so it may have an internal relay. However, it is best to not increase the load on that circuit to be safe.)

(Also, the diodes must be parallel with each other, not series. I.e. joined together on their "output" sides, or "head to head" not "head to tail" … all very technical terms - if I am confusing anyone, just ignore and go with the diagram and picture.)

One additional installation note. I only removed the bottom plastics to do all of the installation and did all of the wiring on the bench with the OPT7 lights, so that when I got to the car I just had to plug things in. The headlamp connectors are up high and if I recall correctly both of them are close to something above them. Easy enough to reach up with one hand and unplug, then re-plug using the add-on harness. But since you are not using the harness, you may need to investigate what to remove up top for adequate accessibility. Hopefully you can disconnect it from below then pull it up through the top to add your tap on the GY-VT wire, or it may be easier to just remove the bumper... Which is pretty easy to do and is shown in several YouTube videos for installing aftermarket turn signals.

As for OPT7's response to both of us about giving up and returning the item. They could easily incorporate the diode pack with an additional pig-tail lead into their design. Since they have all the design specifics of their white LED's and driver circuits, they could use an appropriately sized diode pack instead of us having to "over-engineer" it to be tough enough for an incandescent bulb (could save them space - maybe even circuit board mounted diodes would be adequate). Then they could sell it as is, or up-sell the add-on harness as an option for white running lights. I think their customer base could grow quite a bit for this product. Many others (including @ahl395) were disappointed that they won't run as white DRL's out of the box. I wonder how many decided not to buy them because of that one shortcoming?

Of course, that assumes that you want to have white DRL turn signals. If you prefer them to be off during the day and they are fibrillating when the engine is running, you are screwed and will need to return the Arrows. But the white DRL turn signals look pretty good. For the crowd that prefers the amber, look at the Morimoto or Raxiom offerings.

 

[OnGaurd]

@Grimmer
I have some questions for you
1. Did you install the resistor from Opt7?
2. Can you show me the the wiring and diode hook up?
3. If you did not install the resistor from Opt7 do the white DLRs stay on no matter if the Parking or headlights are on with this hot wire tap?
I have ordered the diode dynamics harness and the trailer diodes to do this but just want to make sure I have everything

 

[Grimmer]

1. No I did not use the resistors from OPT7. I did try them, and they did not improve anything so I left them out. I'm not sure how much load they would add so I opted to leave them out.

2. I don't have photos (edit: photos posted below), but I can try to take some if I open up the fender flap. Also, I made my own diode packs so it won't be as pretty as the etrailer ones. Although I might actually swap them in someday.

3. Yes the white front signal lights will be on whenever the ignition is on OR whenever the parking lights are on.

 

[OnGaurd]

@Grimmer
Ok great one more thing if I understand it will fix the fibrillate, as you like to call it , to work like they should. I’ve been waiting for a year to see if someone would figure this out. I cant believe that Opt7 could not figure this problem out. I would like to thank you for this post on this and answering my questions. These Opt7 signals in my opinion are the best looking on the market and hate that they dont work like they should.

 

[Grimmer]

Yeah, I call it fibrillate to distinguish from hyperblinking which is typically associated with the dash indicator. And they looked like they were having a heart attack / irregular heartbeat.

I found with my Arrows that they worked whenever the parking lights were on, so this whole journey was to ensure that they always had that parking light feed. Worked out for me and I certainly hope that it will work for others too.

My Arrows worked normally so long as the engine was off or the lights were on, so if your engine is running with the lights off and yours don't blink correctly (but otherwise do) and turning the lights on fixes it ... This fix should work for you too.

 

[Grimmer]

I was able to get a few pics without taking much apart... Luckily, one of them included most of the important parts in one shot.

 

[Grimmer]

Here is the headlamp / DD harness...

 

[300mag]

Thanks @Grimmer , diode packs built , hopping to install this weekend. View attachment 351277

 

[Grimmer]

Looks awesome! Nicely done.

At one point I thought about hard wiring the diode pack to the OPT7's so that there would only be one of those "wonderful" blade terminals to receive the drop line from the DD harness...

 

[Grimmer]

One thing I came across was that the green wire on the OPT7 is pretty short. If it is too tight for your diode pack you can try bending the diode leads a bit. Or adding an extension to one end of the green wire.

I added my diode packs without removing the previously installed lights from the car, so I had a limited view and access.

 

[300mag]

One thing I came across was that the green wire on the OPT7 is pretty short. If it is too tight for your diode pack you can try bending the diode leads a bit. Or adding an extension to one end of the green wire.

I added my diode packs without removing the previously installed lights from the car, so I had a limited view and access.

missed this response but exactly what I did, they are working perfectly now. thank you.

 

[Fogg]

Awesome thread - i have just installed the OPT-7 and the not working white light / parking light is driving me mad.

Already been in contact with OPT-7 but they could not help yet. Weird as their marketing is especially mentioning the switchback function. I'm still in contact with them and see what I or they can do. Always a bit more difficult for me as I am overseas...

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