Headlight relays

[Big Red Mach 1]

This has proved to be a pretty long, drawn out thread, but I feel I/we have all learned a lot and that's what it's all about. Thanks to everyone who has added important info to Droptop 73's post and question.

For sure. Apologies to Droptop73 for the hijack, but we now have 3 thumbs up (Chris, Geoff, John) for what I would consider the "Classic Look LED Headlights" with the Hella globes and the fanless LED's listed above (or any similar). Relays don't appear to be needed, but certainly could not hurt. I'd consider those optional. Hopefully that helps Droptop73 and other make some decisions in the future. 

 

[droptop73]

For sure. Apologies to Droptop73 for the hijack, but we now have 3 thumbs up (Chris, Geoff, John) for what I would consider the "Classic Look LED Headlights" with the Hella globes and the fanless LED's listed above (or any similar). Relays don't appear to be needed, but certainly could not hurt. I'd consider those optional. Hopefully that helps Droptop73 and other make some decisions in the future. 

No need for any apologies here! 

This has changed the direction of my build. I went with the relay kit, Hella globes and LED lights. I am very impressed with the results shown in this thread. I don't have power to my lights yet as I'm in the midst of rewiring the car as well. I like the classic look of the Hella globes and LED headlights were in the plan eventually. 

I also decided to use the 71-72 under bumper turn signals and convert the lights in my 73 grille to running lights just to be different LOL... 

 

[Mister 4x4]

The original relay harness I bought got ruined in my accident. I don’t remember where I got them, but it was before I knew that Rocketman sold them. But the one I have now was replaced by the shop that repaired my car and I have no idea where they got them from. From the pics you posted compared to mine the light looks pretty much the same to me.

I think you might've gotten the same one I did, but I can't remember if I grabbed it from NPD or CJPP.  https://www.npdlink.com/product/headlight-power-upgrade-harness-for-two-headlight-vehicles/208636/200546

Right now, I have a set of Scott Drake halogens (https://www.cjponyparts.com/scott-drake-headlight-halogen-fomoco-mustang-1965-1968-1970-1973/p/HL4/), and while they're a LOT brighter than the standard OEM replacements, they're basically just vintage lights that aren't very bright at all (compared to what's available these days, that is).  I also picked up a set of these so I can run H4s (G.E. SilverStars, to be specific), which should pretty much take of any lighting issues.

I also know I need to pick up another relay harness for my '80 CJ-7, so I can run some G.E. SilverStars in it when I get it back on the road.

 

[Big Red Mach 1]

I also decided to use the 71-72 under bumper turn signals and convert the lights in my 73 grille to running lights just to be different LOL... 

I'd be super interested in doing something similar. Will the 71-72 turns bolt right up to the 73? Or are you fabbing some brackets? 

 

[tony-muscle]

I ordered my relay kit from Summit back in 2014.

https://www.summitracing.com/parts/UPD-34263

 

[jpaz]

I think you might've gotten the same one I did, but I can't remember if I grabbed it from NPD or CJPP.  https://www.npdlink.com/product/headlight-power-upgrade-harness-for-two-headlight-vehicles/208636/200546

Right now, I have a set of Scott Drake halogens (https://www.cjponyparts.com/scott-drake-headlight-halogen-fomoco-mustang-1965-1968-1970-1973/p/HL4/), and while they're a LOT brighter than the standard OEM replacements, they're basically just vintage lights that aren't very bright at all (compared to what's available these days, that is).  I also picked up a set of these so I can run H4s (G.E. SilverStars, to be specific), which should pretty much take of any lighting issues.

I also know I need to pick up another relay harness for my '80 CJ-7, so I can run some G.E. SilverStars in it when I get it back on the road.

I think the shop that did work on my car got the harness from NPD. That’s where they get a lot of their parts from. Looks just like the one in my car now.

 I had the Scott Drake halogens too. They were much better than the original lights and probably the best thing Scott Drake made in my opinion. But these new leds are much brighter.

 

[Don C]

The primary reason for this thread was to discus reducing the amperage across the headlight switch and increase the power to and the brightness of the headlights.

Another benefit of reducing the amperage consumed by the headlights is increasing available power (and voltage) to most of the rest of the car. All of the electrical systems in these cars is fed by that fat yellow wire that runs from the solenoid or terminal through the firewall and under the dash, except for power windows, convertible top, and heated rear window. All wire, including copper wire, has a small resistance to the flow of electricity which creates a voltage drop in the wire which is dissipated as heat. The higher the amperage draw through the wire the greater the voltage drop. 

Eliminating the current draw to the headlights, even LEDs, frees up voltage to the rest of the electrical systems, such as turn signals, brake lights, taillights, parking lights, heater blower, radio, dome lights, and the ignition system.

 

[Stanglover]

The primary reason for this thread was to discus reducing the amperage across the headlight switch and increase the power to and the brightness of the headlights.

Another benefit of reducing the amperage consumed by the headlights is increasing available power (and voltage) to most of the rest of the car. All of the electrical systems in these cars is fed by that fat yellow wire that runs from the solenoid or terminal through the firewall and under the dash, except for power windows, convertible top, and heated rear window. All wire, including copper wire, has a small resistance to the flow of electricity which creates a voltage drop in the wire which is dissipated as heat. The higher the amperage draw through the wire the greater the voltage drop. 

Eliminating the current draw to the headlights, even LEDs, frees up voltage to the rest of the electrical systems, such as turn signals, brake lights, taillights, parking lights, heater blower, radio, dome lights, and the ignition system.

As I asked originally " We need relays why?" thanks to your detailed and informative replies, I now know why they are needed. We've been all over the map on this thread and from reading others replies, a lot has been learned, for me especially. As you've read, I made a bad choice and bought a cheapo Chinese relay that did not work. I ought to have at least bought a better quality relay, which is still on the to do list. Adding that can't hurt anything other than the piggy bank.

Thanks Don for your insight, it is much appreciated.

 

[droptop73]

I'd be super interested in doing something similar. Will the 71-72 turns bolt right up to the 73? Or are you fabbing some brackets? 

I swapped the 73 front bumper for the 71-72 chrome bumper and used the 71-72 fenders and valance. The earlier valance has mounting for the turn signals. I'm sure the early turn signal housings could be adapted to the 73 with some effort. 

 

[Big Red Mach 1]

 I'm sure the early turn signal housings could be adapted to the 73 with some effort. 

It certainly seems like there are some "landing pads" for lack of a better term that I could use for mounting/alignment. The 73 urethane bumper hangs pretty low though. I'd like to make those the markers, and keep my turn signals up where they are, just split them. With these new LED's, even with the electronic flashers, when the markers are on, the turn signals don't really "flash" it's more of just a pulse and I don't care for it. Perfect when the markers are off, and perfect in the back regardless. Just those that bother me.  

 

[Big Red Mach 1]

Looks like my best bet is to find a set of these brackets from an otherwise roached 71-72 valance. 

 

[tony-muscle]

I already had relays installed so no issues with current. However, after reading this thread I got motivated to try those LED headlights. They are definitely brighter and whiter. I have not tested them on the road yet, but in my garage I could see the difference. These consume 25 watts and are brighter than the Hella halogen rated at 80/100 watts. The LED lamp is on the driver's side in the picture. I still don't trust how long they will last so I will carry the Hellas as spare.

I got these:

https://www.amazon.com/gp/product/B06XHD78DQ/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

 

[Big Red Mach 1]

I already had relays installed so no issues with current. However, after reading this thread I got motivated to try those LED headlights. They are definitely brighter and whiter. I have not tested them on the road yet, but in my garage I could see the difference. These consume 25 watts and are brighter than the Hella halogen rated at 80/100 watts. The LED lamp is on the driver's side in the picture. I still don't trust how long they will last so I will carry the Hellas as spare.

I got these:

https://www.amazon.com/gp/product/B06XHD78DQ/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

Those are the exact ones I got. They were not available when Stanglover got his, although the ones he got are practically identical, just a different name. They seem to disappear and re-appear from Amazon. 

 

[MKSpeedlab]

Figured I would throw the headlights I put in into the mix as well. They dont look quite as OEM as some of the others posted, but I liked these because they were nice and simple, and were very easy to install. They were a direct bolt-in, the harness plugged right into the factory one, and they do a MUCH better job lighting up the road at night. And no halo rings or built in turn signals which made me happy. The only thing that lets you know is a)the smooth glass front with no ribs or anything, and b)you can see a divider inside them that seperates the low and high beam portions. But I am really happy with them. 

 

[Stanglover]

Thanks for the updates. More good options for members (and non-members) to consider.

I still have not had my car out at night. The weather here has been crap for the last few weeks, but now much better. We seem to go from Winter to Summer lately. I will have to get her out one of these nights, a, to see how much better they are and b, to check the alignment.......... don't want to blind anyone!!! 

 

[Stanglover]

Well, last night I finally got the car out to try out the new LED headlights. I had limited time and it was not yet totally dark, but enough for me get a good look at the difference. The light was white and bright, good spread and on high beam waaay better than the older Halogen bulbs. I still have not installed relays and to be honest, I'm not convinced they're needed, "if it ain't broke, don't fix it".

All in all, a great and simple upgrade at reasonable cost.

 

[Big Red Mach 1]

Well, last night I finally got the car out to try out the new LED headlights. I had limited time and it was not yet totally dark, but enough for me get a good look at the difference. The light was white and bright, good spread and on high beam waaay better than the older Halogen bulbs. I still have not installed relays and to be honest, I'm not convinced they're needed, "if it ain't broke, don't fix it".

All in all, a great and simple upgrade at reasonable cost.

Great to hear Geoff! I'll be using mine this coming Friday night for our monthly meet. We shift to evenings in the summer out here. 

 

[Stanglover]

All, I asked Bill at Hi-Po Parts Garage, www.hipoparts.com for his input as to whether a relay or relays would be needed especially when converting to LED headlights  or in my case, wanting to convert the Mach 1 sport lamps to DLR's. Below is our conversation on the matter. This is not to say there are others just as qualified to offer their opinion or advice, so this is just Bill's thoughts on this. It is my hope that this is taken in the spirit it is intended.

Oops, this copied in reverse order, no idea how to revert it, sorry

 Geoff wrote:

Thanks Bill. I will indeed try that test. That's good information. The headlight bulbs I have do not have fans, but do have heat sinks. Should I need a headlight harness with relays, I'll be back. 

Again if I may, that is great information to pass on. 

HiPo Parts <[email protected]> wrote:

Bob knows his stuff too.  I think people get confused about the need for relays and when you don't "need" them.  That said, it would not hurt to isolate the headlights from the factory harness.  I usually suggest a simple test to see if you would NEED a headlight harness.  Note, just because you don't need it, does not mean that you wouldn't benefit from it.    

1.  Start their vehicle and turn on the headlights (low beams).  

2.  Unplug one headlight while watching the other.  If it gets brighter, then you need a harness.

3.  Carefully, connect 12V from the battery directly to the low beam on the bulb that is not plugged in.

4.  Compare the headlight connected to the car to the one that is getting direct from the battery.  If the light connected to the battery is brighter, then you need a headlight harness.

5.  Repeat steps 1-4 while running the high beams instead of the low beams.   

This may be worth your time to do this test as well.  In your case, if your headlights have built-in fans, then they would need to be running during the test to simulate the full load.  

Thanks,
Bill
HiPo Parts Garage

 Geoff  wrote:

Bill. Thanks for that excellent explanation for the need for a relay on the lights. I agree with you and from my mega knowledge of electrical "stuff" relays would not be needed unless I see a problem in the future. As for the DLR's this would isolate the sport lamps from the rest of the lighting circuit. I find that people seem to get confused whenever they see red lights on at the back in daytime, although it might keep them off my ***! Of course whenever the headlights are on, the DLR's would be on as well. This idea only would work with the Mach 1 sport lamps, so not an option for your basic Mustang unless the low beam headlight could be wired to work as such. I also agree that hiding any electrical changes is key on these cars. The relay kit I bought needed the power wire lengthened so I could hide the relays in front of the battery. The wire harness was barely long enough if I ran it along the bottom of the rad cross member. As I said, it didn't work for some reason, but I wish I'd have smartened up and tried it before I did all the installation, that would have saved me a couple of hours.

Anyway, IF I decide to do the DLR conversion and looking at the harnesses in the engine bay, I will be better off finding a keyed power source under the dash near the fuse block. After all, those two led's won't pull any amount of power. I could probably tap into the radio feed for example.

I thought you used to be a site supporter on the Forum, I didn't see you listed when last I looked. However, I thought you might like to know that any time members talk about changing or adding LED light to the dash or otherwise, chances are they go to ebay or other crappy site. I always ask why? Why not go to our expert at Hi-Po Parts.com and get the best parts and service out there. Most of the older members agree. I am very happy with the LED's I got from you, no problems at all. I tell anyone I can about your business whenever the opportunity arises, Yes even GM guys!. 

As for the explanation for relays you provided above and due to the amount of confusion out there, I would like to quote you, or simply cut and paste to the forum with your permission of course. The only other member/site supporter who does relays is Bob at Rocketman's Classic Cougar Innovations so I would not want to step on his toes so to speak.

Geoff.

 HiPo Parts <[email protected]> wrote:

Yes, you have the correct headlights for using LED bulbs.  Those are the ones I have as well.  I do not use a relay harness in my 71 with the LED headlights.    

You probably know all of this, but I'll cover it all to be safe.  The purpose of the relay harness is to pull power directly from the battery to run the headlights.  This is done to compensate for tired wiring.  In most older cars, the wiring cannot carry the current required to properly light the incandescent headlights.  As a result, the headlights often seem dim and even yellow in color.  The harness plugs into one of the factory headlight plugs to get the signals for the low beams and high beams.   The harness provides new connections for the headlights and then connects to the battery for the power to the two circuits/relays.  The premade harnesses can be hit and miss.  I am not sure if they would do anything for a vehicle with LED headlights.          

We offer all of the parts for customers to build their own relay harnesses.   When I build a harness for a car, I try to make it invisible.  I want all of the relays hidden and the wiring run in places that you will not see it.  I even connect to the distribution block or the solenoid to help keep the underhood clean.  For those reasons, no premade harness would ever work for me.  I find that most customers prefer work done that way.  A little extra time and a little extra wire can make a huge difference.  We have a diagram on our website with links to all of the options to build your own harness.  Here is that page:   https://www.hipoparts.com/headlight-wiring-harness-project/  Customers can even download and print that diagram.  Please share that if someone needs it.  You will see we offer several different types of the connectors, relays, bases, and other parts to accomodate what works best for each specific car.  We have found that by allowing customers to mix and match, they get better results.

It sounds like the DRL suggestion makes all of your running lights work when the car is on.  That is not a bad option.  I typically leave mine on when driving.  It looks better and makes the car more visible. You could use a relay to power those, but I do not think the system in your car is that taxed.  Your car has LEDs in all of the bulbs, so that should negate the need for setting the circuits to be powered via relay.   With LED bulbs, that should eliminate the needs for such changes.  Unless you are seeing a problem, I would say leave it alone.   

Thanks,
Bill
HiPo Parts Garage

 Geoff  wrote:

Good morning Bill. Thank you for getting back to me. Nice to hear from you.

I'm not sure if you even go on the 7173Mustangs.com forum these days, but there was a thread that brought up the need, or supposed need for headlight relays. Title; Headlight Relays. In this, we discussed LED headlights as well and this led me (and others) to purchase Hella headlamp globes and H4/9003/HB2 headlight LED's. I'm attaching the receipt from Amazon.ca ( yeah, I know!!) These Hella globes look quite like the originals, so no-one would know if they are not turned on. The installation was very easy. The Sealight bulbs (there are other similar brands) were just plug-n-play. I did need to add a couple of zip ties just to keep it neat. Now, I did also purchase a cheapo relay kit, but for some reason, it did not work. I actually suspected it had been purchased and returned because of the way it was packaged and the instructions were missing. I sent it back for a refund. As you say, probably not even needed with the LED bulbs. I have not yet had the opportunity to drive in total darkness, but I did take the car out around 9:30 and the beam is way better than the Halogen bulbs. I may need to re-aim the left side headlight.

As for converting the Mach 1 Sort lamps to DLR's, Midlife, the site vendor for harnesses, told me that all I need to do is at the dimmer switch, locate the input power wire #15 on the diagram, then at a convenient point cut and terminate the wire from the switch to the sport lamps and find a 12V keyed wire to connect it to. He does say "a relay", but I don't think he meant a relay as such, just a relay as in a connection wire. As I have your special LED sport lamp bulbs, I will not add a separate relay. The question is, where to connect the new wire to the sport lamps? I likely could just connect to the 12V feed to the coil. That way I won't need to pull the dash apart again!.

DLR's in Ontario can be orange, so no worries there. I'm just getting tired of people apparently not able to see my 6 foot wide car coming at them. I don't have to convert or add DLR's, just something I thought about doing.

So, what do you think?

Regards,

Geoff. 

 HiPo Parts <[email protected]> wrote:

Geoff:

I think they are telling you to run them off a relay due to the higher draw on the circuit.  If you have converted everything to LED, I doubt that running them off a relay is necessary.  The circuit should be able to power the headlights without a problem.  They should draw a lot less current than any incandescent headlight bulb.      

Tell me more about what you are running.  LED headlights can be really good, if you use the correct type headlight to properly use the light.  Most people buy the cheaper headlight housings and they get awful results and then blame the headlight bulb.  That is why we do not sell them.  Also tell me how you plan to wire the DRLs so I can understand what parts you will need (if any) to accomplish the project.  How do you plan to wire those grille lamps to function as DRLs?  What would trigger them to light?

Thanks,
Bill
HiPo Parts Garage








[SIZE=9pt] [/SIZE]





[SIZE=9pt] [/SIZE]



[SIZE=9pt] [/SIZE]





[SIZE=9pt] [/SIZE]



[SIZE=9pt] [/SIZE]





[SIZE=9pt]Hello Bill.
Since I added all your LED/SMD light bulbs to my 71 Mach 1, I would like to convert the grill sport lamps to DLR's. I know basically what to do to separate them from the main light circuit, but I'm told I need to run it through a relay, not sure why as the sport lamps are low draw SMD's. Also I upgraded the head lights to H4 9003 LED's without relays, but again told I should add them. Confession time, I bought a cheapo relay kit off Amazon, but it did not work, sent it back.
I see you list many relays and components, but I'm not sure what to order. Can you assist me and suggest what would be best. I can make my own harness if you don't have relays in a kit form.
Thanks again Bill,
Geoff.[/SIZE]






HiPo Parts Garage
https://www.hipoparts.com/

 

[jpaz]

Wow that’s so long I couldn’t read through it. Ever since I put the headlights on a relay the dash lights have been even brighter than just going to the led lights in the dash. No brainer. Then going to the leds for the headlights, dash lights are brighter than ever!

 

[midlife]

OK...I read it too, but your rationale for DRL's through the sportslamps were not as clear as what you told me, which is why I suggested a relay.  You want the DRL's to work without running lights on the rears, which means there is no "parking lamp" circuitry (65-68 has it) or other circuit that is distinct from other functions from the headlight switch.  Tapping into a RUN-only line is what you want (they will be on anytime the engine is running), but unless you use LED's in the sportslamps, the current draw will swamp most of the run-only lines available in the engine compartment and either blow a fuse or cause a fire if not fused.  Use of a relay to power the sportslamps, whether LEDs or incandescents, is safe and effective.  If you use LED's without a relay and someone else comes along and puts in incandescent bulbs, then the risk is there.  Spend another $10 and eliminate a risk.