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How to Make a Relay Harness!

43K views 34 replies 15 participants last post by  Alphawon1 
#1 ·
There isn't really a thread here for making your own relay harness...
so here's a clean how-to:
- 20ft 14 Gauge wire: Autozone/strauss has them for $ 5.00

- 10 sets of Disconnect Pairs(male and female) 14gauge: autozone has them for $ 5.00

- 12 Volt 30amp Relay: autozone or strauss has them for $ 5.00

- Black electrical tape: $ 0.99

- fuse holder 14 gauge: $1.50

- 9006 male connector (only one is needed)
................
Let's start by simply gathering the parts together...
And following this simple drawing you'll be set =]

- Start by cutting two wires that can be 4ft long. This will be the positive and negative for the ballast that will be located further away from
- Cut two wires that are 1 ft long. This will be for the negative and positive for the ballast that's the closest to the relay harness.
- Cut two wires that are 6 inches long. This will go to the 9006 female for a plug and play.
- Use the cut wires above as you wish on the description below. Remember, one headlight is almost touching the battery so use the short ones for the ballast that will be connected to such headlight and 9006 female connector.
Now let's go to the drawings:
Note: The drawings have numbers where it says relay that's because the relay has 4 teeth. Each teeth is already numbered on the relay itself. Look for them.
1.Ground or negative: Prepare both with one disconnect female at one end only...not both(the ballast + and - wire will have disconnect males)...At the very end of the wires you have to attach a single wire and wrap them up in black electrical tape and attach a terminal to the end. This will be bolted onto the chassis =]



2. Grab 2 wires and prepare 2 ends with female disconnects. Unite/crimple the other ends and attach another short wire with one end having a female disconnect.



3. Grab one wire and attach it to the fuse holder and wrap electrical tape around it. The to the other end of the fuse holder, attach a terminal...



4. Grab the 9006 male connector and add extensions to the wires if u need them longer...then attach two female disconnects. You're done with the wiring!


Now attach everything and your relay harness is f*ckin done! =]
You just saved yourself 50 bucks. (taken from hidplanet.com)
Here is where everything should be attached to on the relay.


Final Product: it should look similar to this...
 
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#34 ·
Nice... I always use this.. You dont need the diode going to the plug. Thats for Bi-xenon
[URL=http://img99.imageshack.us/img99/2425/hidharnesssinglefilamenyx0.gif]image
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Sorry for asking the question years after the fact, but I'm putting HID's in tomorrow, with projectors and I need to know about this diagram. I don't want to use the projector for my hi's I want to just use the halogen for them. So in that case do I just not hook up the two wires out of the projector, and leave it at that?

Also for the HID's I have Morimoto ballasts. I got a harness with a relay on it etc, from TRS with the order. They gave me two of them, although I'm not sure why. Do I just plug the female into the driver side 9006 oem connector, then from the harness there are two male connectors. Those go to the driver side ballast, and the passenger side ballast right? So does the oem connector on the passenger side just get left hanging then? Tuck it away or what? I'm kind of confused. Hopefully someone can help me out here before tomorrow afternoon.

Thanks!
 
#5 ·
Design comments

This design described below is essentially a shade-tree copy of the existing commercial designs for retrofit kits. My comments on it are:

Ballast and relay connections as described have a very high probability for failure due to either corrosion, poor crimping, and bad insulation. The design as described accentuates all 3 of these failure points. Proper crimping of the blade connectors describes require special tool and even with the tool can be a hit or miss proposition. Electrical tape used in a harsh environment like a wheel well or engine compartment will surely start to unravel over time, and can cause shorting issues.

To correct this. I would recommend the following:

1. The Ballast connections should use 9006 female connectors that are soldered and shrink tube insulated to the wiring runs, rather than using spade crimp connectors. Of course the ballast should be installed with the connector pointing down, and with a coating of lithium grease to prevent moisture buildup.

2. The relay should be connected to a relay plug pigtail, with all of the connections soldered, and shrink tube insulated instead of spade connectors. The relay connection spades and receivers should have a liberal coat of lithium grease applied to them as well to prevent moisture.

Lastly, since this item should not need any adjustment or access after it is tested, I recommend that the entire relay assembly be dipped in a moisture barrier/insluator rubber coating such as Plasti-Dip. This will insure that the relay will be protected from the elements.

3. It is important to fuse the entire circuit with a 20 amp fuse and not a 30 amp. This is because if there is an over-current event on the harness, you want the fuse to blow before any damage occurs. Further, it is important to fuse both the ballast supply legs at 10 amps so that in the remote possibility that there is an over current situation with one of the ballasts, only that leg will open and leave the other headlight on. The logic of this is primarily for safety, especially since the fuse would probably open with the lights are on, which is usually at night when you are driving down a road. The last thing you want to happen is have both lights go out because of a poor fusing scheme.

I know that there are a few of you that are still firmly believe that ballasts draw hysterical levels of current, and huge fuses are necessary, but for the more popular retrofit kits that are available today these beliefs are simply incorrect.

If these additions are added to this design, it will bring this harness design up to an approximation of what each and every one of you already have in your Civic with your existing lighting wiring.

Now the downside of homegrown harnesses. By adding this additional harness what you add is multiple additional failure points that you did not have before, plus wasted time, and effort.

Now the question you have to ask yourself is "Do I really think that I can design, manufacture, and install a lighting subsystem better than an automobile manufacturer can?" From what I have read on this board the answer would be no. There is no one here on this board, including myself, that has better smarts than the engineers at Honda when it comes to designing lighting systems.

So if you insist on being a hard head, and come hell or high-water think that you are better off with an add-on lighting harness, then at least do it in a way that will create fewer headaches for your self moving forward. :thumb:
 
#7 ·
striker_1818 said:
yeah man that's why us hard heads know Honda designed their wiring for halogens otherwise HID's wouldve been an option =]
crimpling or soldering doesn't make a difference but for safety snd longevity i'd use soldering(10bux on radioshack)...
You are sort of correct, the lighting wiring harness for the Civic is the same world-wide for HID and Halogen, and in other countries such as Canada where the Civic is marketed under the Acura brand, HID is an option. In Japan HID is an option on the JDM Civic with the same harness for Halogen and HID. The reason that HID is not available on the Honda Marque here in the US is that upmarket stuff is reserved for the Acura brand.

Click here for the JDM Civic website. There is some really interesting stuff for JDM.

One interesting item if you drill down to the Civic options is that the HID factory lights use reflectors and not projectors.

If a wire is crimped with a industrial crimping tool, the connection is as good if not better than solder, but crimping using a hand tool is a 50-50 proposition of getting a good solid connection. A hand soldered connection has a much higher level of reliability than a hand crimped connection.
 
#8 ·
no **** I'm aware of it.
CSX rings a bell?
HID reflectors and halogen reflectors whereas the design is different for such different optics...
Again each ballast brand draws a different current depending on the technology being used. My denso's pop up my fuses :(
 
#11 ·
right! that's probably one of the reasons they replicate the same ballasts and using some of their parts for theirs. But quality and quantity are different. Another reason why I go with OEM ballasts is because they are designed for an everyday use and to outlast your car while aftermarkets are replica's only.
You've told me once to stop following advices from people that say something about products i know nothing about but to get some first-hand info about such products...
Well, the same goes to you. It's abit early to tell whether the ballasts you're using are the same or better than OEM ones.
 
#13 ·
One way of measuring quality of a product is to ask the vendor what their warranty return rate is. If they won't discuss it, be suspicious. If it is low, they will want to promote that, and this is usually with at least a 1-year warranty.

I picked the lights I have primarily because of discussions I had with the vendor and the manufacturer on their warranty. Now granted I am somewhat fortunate because of contacts that I have in the Guangdong Province of China where my lights were manufactured. (Same place your iPod comes from). This gave me the opportunity to check out the manufacturer a little bit more throughly than your average person, and gave me the confidence I needed to make the purchase. But at the end of the day, if a ballast can have a MTBF life of 3-4 thousand hours, then it will effectively last the life of the car it is installed in. 3-4K hours is pretty standard for this type of device, and at $75 a lamp is competitive with other alternatives. If a light or ballast does not fail on the burn-in rack at the factory, it has a very good chance of lasting the full design life.

You will find in the next few years that while many designs for ballast will originate in Europe or Japan, almost all manufacturing will be done by the OEMs with facilities in China. In addition, there are many extremely competent ODMs (Original Design Manufacturers) in China that are creating new more efficient and cost reduced ballast and lighting designs. Click here to see some of them To suggest that Chinese manufacturers are simple knock-off copycats show a real lack of understanding of todays automotive electronic market. These guys are the leaders in HID and LED technologies.

While it is easy to discount a bad experience with a retrofit kit to the manufacturer, now days the competition for manufacturers is such that a bad one does not stay in business long, and with Asian manufacturers, quality is job 1.

It is unfortunate but the majority of bad experience with installations or by reliability are self-induced by either over confidence in ones abilities, and badly done installations, or by second guessing a manufacturer, and trying to make a "better design".
 
#14 ·
so if i install an hid kit in my car where the bulb keeps flickering and then after a week they die thats my problem, right? I did the installation wrong. But how can someone install it wrong? It is really a plug and play item. There's little to no room for failure while installing it.
BTW of course China is the leading country in HID kits... Every replica of everything that was done by european countries or elsewhere, the chinese market will replicate it.
BTW, 1yr - 3yr warranty means nothing when you can get an oem kit that will outlast your car aka 10 yrs...
there are still old valeo's from 1998 taken out of bmw's in working condition...
 
#16 ·
Superb DIY, complemented by orientexpress, it's great job boys ! I still have 2 questions:

1-it's not better to do a independent setup for each side of HID ? I mean, one relay and one fuse per side ?

2-On some aftermarkets FogLamp, the black connector goes directly on the frame instead of the black pole of the battery. What's better and why ?
 
#17 ·
seaman said:
Superb DIY, complemented by orientexpress, it's great job boys ! I still have 2 questions:

1-it's not better to do a independent setup for each side of HID ? I mean, one relay and one fuse per side ?

2-On some aftermarkets FogLamp, the black connector goes directly on the frame instead of the black pole of the battery. What's better and why ?
Either way is fine...
H1/h3 fogs will have a positive for the bulb and then it will ground itself from the original oem wiring to the projector or housing or frame...
take a look at this H3 projector...
 
#21 ·
a diode idk but i know it's a one current flow of electrons lol that's about it...
And no, the setup on our cars is an 18gauge ground and positive that comes from a switch then wired to a fuse. Point of a relay harness is to make a switch when a ballast powers up thus all the electrons will come from the battery and then once the ballast reaches warmup temperature, the switch will again activate and the 4.5amps will be extracted from the oem harness.
 
#22 ·
striker_1818 said:
And no, the setup on our cars is an 18gauge ground and positive that comes from a switch then wired to a fuse. Point of a relay harness is to make a switch when a ballast powers up thus all the electrons will come from the battery and then once the ballast reaches warmup temperature, the switch will again activate and the 4.5amps will be extracted from the oem harness.
Huh? what are you trying to explain here?
 
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