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 ass! 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
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[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/
