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Discussion Starter · #1 · (Edited)
Edit I changed the name of the thread due to my latest research. See post #4 below.

I'd like to figure out what exactly I want to do with my front inboard (i.e., adjacent to the grille) lights. But first let me tell you about my day:

Today was so much fun, because I went to a pick & pull yard for the first time ever. I've been to "conventional" junkyards, but this is so much cooler. I mean they give you a wristband; it's like going to a nightclub, and nobody keeps watching over your shoulder.



I picked up some chrome door knobs (because I love bling - don't judge)...



...and these three-prong plugs/harnesses, which brings me to the topic of this thread:




The Factory Setup

As you all know, the inboard parking lights in the front are just that: parking lights. That was just a waste in my opinion, since there are already parking lights at the corners.

The Current Status

Currently I have white 3157 Zevo LEDs in this spot. I modified the plug by moving the parking pin into the major slot, i.e., the LEDs run on the bright LEDs when the parking lights are on.
My rationale for this was that I would use the parking lights as DRLs. While that works great during the day, the problem is that the LEDs are too bright at night. I absolutely hate cars with lights that glare, are ill-aimed, etc., so I don't want to be guilty of doing that myself.



Changing the plug back to running on the minor pin would not really help, because then the LEDs would be quite dim for DRL duty. (Zevos have great contrast between the Major and the Minor LED).

What I Want and Don't Want

  • With the three-prong harnesses/plugs I picked up at the junkyard, evidently I want these lights to have dim and bright functionality going forward
  • I do want some sort of DRL function (but it does not have to be automatic)
  • I like using LEDs in general, but I don't really want to add any resistors
  • For the High/Low beam headlights, I want to keep incandescent bulbs; I don't really trust LED replacements, especially considering that their cooling fans would be exposed to the elements inside the engine compartment

Option 1

  • Make front inboard lights amber incandescent parking and turn signal lights
Advantage: Since I would then have two incandescent bulbs in the front per side, I could use an LED brake/turn bulb in the back without having fast flash (cruise control wouldn't be affected since I still have an incandescent CHMSL).
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Disadvantage: No real DRL function other than driving with parking lights or just driving with headlights on during the day.

Variation to Option 1

  • Make front inboard lights amber LED parking and turn signal lights (while corners remain incandescent)
  • This would effectively give me front sequential turn signals because the LEDs light up faster

Option 2

  • Keep the white LEDs, but install a DRL module
  • DRLs would use the bright LED elements; parking lights would use the dim elements
Advantage: Real DRLs during the day; white parking lights without glare during the night
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Disadvantage: This seems complicated. I'm not even sure where to source such a DRL module, and then where to get ignition power from in the engine compartment.

Option 3

  • Same as above, but without the DRL module
  • I would run a wire through the firewall and place a switch on the dash
  • This would control the bright LED elements in the inboard lights for DRL duty
Advantage: Very easy to do; real DRLs during the day; white parking lights without glare during the night
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Disadvantage: I'd probably constantly forget to turn off my DRLs.

Your Thoughts?

The best in my opinion would be some combination between option 2 and 3, i.e., something that doesn't require an additional module under the hood, but that has some level of automation (auto on with ignition; auto off with headlights on). How can I accomplish this? (Does anyone have a wiring diagram of the headlight switch by the way?)
 

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1997 Thunderbird LX Sport
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I liked the idea of adding drl when you first did it but I thought that if did it I would do option 3. I want to put 3 switches where the change holders are. 1st for fog lights, 2nd for drl, 3rd for amp/subs.
I think I would want to be able to turn them off when desired.
 

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Discussion Starter · #4 ·
I may have found a solution!

I am reading Ford headlight switch diagrams, and apparently there is a circuit 484 (O/BK) which is hot when the ignition is on but off when the switch is turned to Parking or Headlights On.

This circuit is used to illuminate the radio LCD during the daytime.

Could I use this circuit to power my DRLs?
 

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I may have found a solution!

I am reading Ford headlight switch diagrams, and apparently there is a circuit 484 (O/BK) which is hot when the ignition is on but off when the switch is turned to Parking or Headlights On.

This circuit is used to illuminate the radio LCD during the daytime.

Could I use this circuit to power my DRLs?
Good idea I would assume so. Depending on what LED's you are powering, it would probably be a good idea to put a relay in so too much current isn't drawn through the 484 circuit.

Might use this idea myself. I need to replace my OEM headlights and will probably rewire it then
 

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Discussion Starter · #6 ·
Depending on what LED's you are powering, it would probably be a good idea to put a relay in so too much current isn't drawn through the 484 circuit.
Well, the whole point of this idea is not having to add a relay. But I see your concern. I was hoping some electrical experts would chime in.
 

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Safest bet is to add a relay. But...
-What is the fuse size on that ckt?
  • What all is powered by that ckt?
  • What is the current draw of the LED lights your installing?
 

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Discussion Starter · #8 ·
Safest bet is to add a relay. But...
-What is the fuse size on that ckt?
  • What all is powered by that ckt?
  • What is the current draw of the LED lights your installing?
I don't have a service manual or wiring diagrams. Googling only gets me so far.
I was hoping someone here could answer those questions.

The power draw of 3157 Sylvsnia Zevo LEDs on the bright element per the packaging is 1.7W per bulb. There will be two bulbs total.
 

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1994 Cougar XR7 DOHC/5-Speed
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I may have found a solution!

I am reading Ford headlight switch diagrams, and apparently there is a circuit 484 (O/BK) which is hot when the ignition is on but off when the switch is turned to Parking or Headlights On.

This circuit is used to illuminate the radio LCD during the daytime.

Could I use this circuit to power my DRLs?
What year is your wiring diagram/EVTM for? The radio display isn’t a backlit LCD but a VFD display, it uses the illumination circuit(LG) as a signal to dim the brightness of the display internally when the lights come on. I don’t believe this 484 O/BK exists, but if your using a Ford EVTM tell me the numerical section to look in and I’ll check again.

I think you’ll need a relay one way or another, find a wire that’s on with ignition and run that to 30, with the light end coming off 87a(normally closed) and then for the coil energize use the parking light circuit to power that so when the switch is turned to park/headlight the relay will open the circuit and shut off the DRLs

You don’t need a DRL module. The only purpose of those is when you are using the actual headlight bulbs as a DRL and the module runs the high beams with a pulsed signal to make it less intense. With LEDs in the park position of the housing you definitely don’t need that
 

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Discussion Starter · #10 ·
What year is your wiring diagram/EVTM for? The radio display isn’t a backlit LCD but a VFD display, it uses the illumination circuit(LG) as a signal to dim the brightness of the display internally when the lights come on. I don’t believe this 484 O/BK exists, but if your using a Ford EVTM tell me the numerical section to look in and I’ll check again.
I don't have the manual. What I found googling were diagrams for F-150 of the same year. I was hoping that the circuit would also exist on MN12 - it was worth a shot.
 

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Discussion Starter · #14 ·
@XR7-4.6 ,

Where would be a good place to get ignition power in the interior? I think what I'll do are DRLs with a manual switch. I just want them to draw from a circuit that is off when the ignition is off; that way I cannot forget to turn them off.

Whenever, I use the headlights, I'll just have to remember to turn them off. I think I can live with that.
 

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The radio has both an ignition and a constant 12v. Most cars are set up like that. Probably one of the easier ones to tap off.

Off topic, but for my aftermarket radio I ran the dimmer circuit from the now unused cigerette lighter bulb, to activate the dimmer function.
 

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Honestly it would be cleaner to use a relay(preferably 2), there are numerous and way easier to access hot-in-run wires you can tap into to power the lights, and the parking lights obviously as a depowering trigger for the switching relay. You could avoid running any wires through the cabin and the hot in run circuits you can find under the hood are mostly beefier wires than most of the small gauge wires you’d be grabbing from inside the dash(of which I feel adding a relay and a separate fuse is necessary insurance)
 

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Discussion Starter · #17 ·
there are numerous and way easier to access hot-in-run wires you can tap into to power the lights
For example?

I just figured interior would be good so the relay isn't exposed to the elements.

Speaking of which, could you show me a good example of a relay (link)?
Autozone today was less than helpful. I told the lady I was looking for a relay for such and such purpose. She asked the usual year, make and model. And I said no, it's not like that... We didn't get anywhere.
 

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For example?

I just figured interior would be good so the relay isn't exposed to the elements.

Speaking of which, could you show me a good example of a relay (link)?
Autozone today was less than helpful. I told the lady I was looking for a relay for such and such purpose. She asked the usual year, make and model. And I said no, it's not like that... We didn't get anywhere.
Off the top of my head the red ignition power circuit that powers up the fuel injectors, coils, and active sensors like the MAF, that’s hot in run. There are a bunch of other ones that are switched through the CCRM.

Relays are generic, no need to ask at the counter, you can find them in the aisles of a parts store along with weatherproof connectors for them, they’d look like this



The main thing to look for is one with 5 pins, with fifth being the normally closed 87a, 4 pin types won’t work for this purpose.

Most relays conveniently have the diagram molded into the sides like this, the way you’d wire it would be to run the hot-in-run wire you tapped into to 30, the wire(s) to the light sockets to 87a, the parking light wire to 85, 86 to ground, and leave 87 open
 

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Discussion Starter · #19 ·
@XR7-4.6 , ok, I'm liking this idea more and more...

One thing I don't understand: why would a 4-pin relay not work, yet I'm leaving 87 open (so I'm only using 4 out of 5 pins)?

Also, would there be any harm in using the low-beam lead as a trigger instead of the parking lead?

And finally, you mentioned adding a fuse earlier. Where would I do that? Consider that we're talking about two LEDs with a total output of 3.4 Watts; isn't that minuscule?

(Sorry, I'm a total newbie at this.)
 
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