New Headlight Wiring

[snailwagon]

My 69' fj55 has very dim headlights; I always drive with my brights on and have never been 'flashed'. I'm sure the wiring is also pretty old and borderline.

So I was orderning some parts and upon impulse bought some Hella H4's and the Hella relay w/ fuse from MAF. I understand the basics of wiring in a relay, but am confused. The bulbs in the Hellas are 55/65. To use these, do I need two relays? - a seperate relay for both the high and low beams? The relay that came with the lights is a four prong (30: Power, 85: Ground, 86: Trigger, 87: Headlight Output, or so I think). Also, the Hella Relay is only a 15A, is that sufficient? Or is a 30A more appropriate?

These bulbs are replacing my stock bulbs, so I will be utilizing stock switches and do not want to kill them.

Thanks

 

[joeyg1973]

I am going to tell you what I tell to everybody that wants to do a quick fix to get brighter headlights. Your original wiring harness is close to 40 years old... it is wired to a standard that is so bizarre that it often makes my head hurt (hazard light switch and wipers are just retarded). All the plastic or even possibly cloth is either rotted out or dried out.


Buy a new wiring harness and start over... you can't polish a turd. Get yourself a GM CS-144 alternator while you are at it and toss the maybe 25 amp alternator that is stock.

 

[crushr]

You dont need to replace your wiring harness or your alternator to get brighter headlights. Many outfits including painless wiring sell relay kits that bypass much of your original wiring and allow you to run much higher wattage bulbs if desired.

Painless Performance: Keyword Results

 

[ocdbeetle]

Coolerman pointed me to this site for info....You can read about the headlights and relays here...Great info...

Look at the "brighter headlights" link....actually read them all...

MadElectrical.com - Electrical Tech

 

[bsevans]

My 69' fj55 has very dim headlights; I always drive with my brights on and have never been 'flashed'. I'm sure the wiring is also pretty old and borderline.

So I was orderning some parts and upon impulse bought some Hella H4's and the Hella relay w/ fuse from MAF. I understand the basics of wiring in a relay, but am confused. The bulbs in the Hellas are 55/65. To use these, do I need two relays? - a seperate relay for both the high and low beams? The relay that came with the lights is a four prong (30: Power, 85: Ground, 86: Trigger, 87: Headlight Output, or so I think). Also, the Hella Relay is only a 15A, is that sufficient? Or is a 30A more appropriate?

These bulbs are replacing my stock bulbs, so I will be utilizing stock switches and do not want to kill them.

Thanks

I bought the Painless relay harness for headlights. It works great and require only a ground and battery 12v. The old headlight plug plugs into this harness and that is what switches from low to high. I also have the Hella headlights and with this harness - YOW!! those high beams let you see into the future. I did have to trim about an 1/8" off the factory plug so it would fully seat in the Painless plug.

Painless Headlight Harness

 

[Pin_Head]

You only need relays and new wire if the new bulbs exceed the current carrying capacity of the wires. If the bulbs use more power than the existing wiring can handle, then you will need larger wire and two relays; one each for high and low beams.

It is possible that the reason your bulbs are dim is that you have a bad connection somewhere upstream of the bulbs.

Take MadElectric advice with a grain of salt because they want to sell you solutions to things that aren't a problem. Some of their advice is specious.

For example with their schtik on voltage drop: While they are right about there being a voltage drop, this isn't a big enough problem for the auto engineers to worry about using their solution. It is the power (volts times amps) transmitted by the wire that is most important, not just the voltage that MAD focuses on. The cheaper and easier way to get brighter lights is to use a higher power (watts) bulb. With a higher watt bulb, the circuit carries more amps and therefore more power even though there is a slightly greater voltage drop because of the increased current. Auto engineers know that it is wasteful to use too large a wire for the application, which is what MAD is selling.

 

[jimhendrixx]

Then why am i kicking myself to rebuild my stock harness on my 1973 fj55?

I like stock!

 

[snailwagon]

I'll skip out on the new wiring harness. The reason I wanted to use relays is because I doubt those skinny little oxidized wires could handle the load. When you slap a relay in you use new wire rated for your application (I have a few rolls of 12g, which I was planning on using), solving the need for a new harness.

I assumed the lights were dim because the vehicle was manufactured 39 years, 11 months ago. I've been driving it like this for about 5 years now, and it has always been the same - headlights have been replaced once with el cheapo units.

The alternator is slightly higher output from a later year cruiser and the battery is about the best you could buy, but with a radio being the only other piece of electrical that gets used much I doubt I really need a new alternator.

So the answer I guess is yes, I should probably run a relay for both low and high beams.

 

[crushr]

yep - you need to use 2 relays. The Madelectrical site should give you some insight on wiring it up. Contrary to some folk's assertion, the voltage drop through the factory harness to the headlights is quite substantial, especially after 30-40 years. That voltage drop results in dim headlights. Using higher wattage bulbs in a marginal wiring system is asking for trouble. Installing a $20 eBay relay setup made a huge difference in the brightness of the headlights in my '68 FJ40.

http://www.madelectrical.com/catalog/rly-1.shtml

 

[Pin_Head]

the voltage drop through the factory harness to the headlights is quite substantial, especially after 30-40 years.

That just means that your wiring is bad with one or more high resistance/corroded connections somewhere. Fixing it would make your lights brighter too and you may have to fix it anyway if it gets so bad that it won't operate the relay.

That situation is different than the MadElectric situation which claims that the normal, good condition wiring of modern cars is too small because it has a 2V voltage drop. That is the one that is a solution for something that is not a problem. If you really want 15% brighter lights than the Toyota engineers provided, just get a 15% brighter bulb.

 

[cruiserbrett]

I agree with Pin Head.

While the wiring is old, there are many things you can do to make it better. First off, make sure grounds and other connections are clean. electrical contact cleaner is good for cleaning out the connectors.

Secondly, the headlight switch itself is pretty easy to take apart and clean. over time oxidation forms on the copper contacts and reduces the voltage available to the lights. simply remove the switch, pry the tabs up and clean it out. be careful to keep a reign on the small springs and detent ball.

The relays are nice, you will need a high and a low beam relay, and they are all labeled per the bosch standard these days. web search will net the proper connections for the 30, 87, 86 ect #'s...
However, they are not really that needed. I have hella H4's in my FJ55, and almost never use the brights. Its as bright as my 2006 Dodge ram, without anything other than plug and play bulbs and reflectors.
Lastly, el cheapo bulbs arent going to net the best output. Get some halogens.

 

[Coolerman]

That situation is different than the MadElectric situation which claims that the normal, good condition wiring of modern cars is too small because it has a 2V voltage drop. That is the one that is a solution for something that is not a problem. If you really want 15% brighter lights than the Toyota engineers provided, just get a 15% brighter bulb.

One of the few times I have to disagree. Our Cruisers are 30+ years old and the stock lamps at the time were sealed beam. The wiring was marginal then for that style lamp. If you upgrade to halogen lighting it WILL appear brighter, but you are not getting the full benefit of the new lamps and run the risk of burning out the headlamp switch which is NOT rated for that kind of load.

A 2V drop in the headlamp wiring (from 13.8 to 11.8) will reduce the head lamp output by a whopping 45%.

I researched this a long time ago when I wanted to update my 2000 Nissan Xterra lightning. The best site I found for a layman's description of how to correct this issue is: Daniel Stern Lighting Consultancy and Supply

Here is a direct quote from that page:

"In many cases, the thin factory wires are inadequate even for the stock headlamp equipment. Headlamp bulb light output is severely compromised with decreased voltage. The drop in light output is not linear, it is exponential with the power 3.4. For example, let's consider a 9006 low beam bulb rated 1000 lumen's at 12.8 Volts and plug in different voltages:

10.5V : 510 lumens
11.0V : 597 lumens
11.5V : 695 lumens
12.0V : 803 lumens
12.5V : 923 lumens
12.8V : 1000 lumens ←Rated output voltage
13.0V : 1054 lumens
13.5V : 1198 lumens
14.0V : 1356 lumens ←Rated life voltage
14.5V : 1528 lumens"

The actual formula for calculating this drop in lumens is:
Lr = (Va/Vd)^3.5*Ld, where Lr is re-rated lumens, and Ld is design lumens, and Vd is design voltage and Va is applied voltage.

Here is a diagram of how you should wire your headlamps for maximum brightness:

 

[crushr]

Once again Coolerman delivers the goods. I looked for but couldn't locate the Daniel Stern Lighting link - great site!

 

[Pin_Head]

The wiring was marginal then for that style lamp.

We can disagree about that. Toyota knew about what kind of bulb it wanted to run and it knew about voltage drop.

The calculated voltage drop in a 12 foot, 16 ga circuit at 12 V and 10 amps would be about .6V, so if you have a larger drop, your wiring is bad and needs fixing.

I will admit that installing a new circuit and relays may be easier than actually fixing the problem, but it is a band aid. If you want to run much brighter bulbs, you will need bigger wire.

I noticed Mr. Stern is also selling you solutions to things that aren't a problem. Find me a guy that isn't selling something that says that factory engineers use wire that is too small.

 

[ocdbeetle]

Find me a guy that isn't selling something that says that factory engineers use wire that is too small.

The problem is - the factory engineers may not make the buying decisions...They can design and recommend but economics always looks for a compromise....It may be in wiring sometimes...

 

[Coolerman]

We can disagree about that. Toyota knew about what kind of bulb it wanted to run and it knew about voltage drop.

I'm sure they did, but they still used a wire size that causes a voltage drop enough to lower light output.

Their reason may have been to increase bulb life? Just as output goes down dramatically when voltage to the bulb is reduced, bulb life goes up.

The calculated voltage drop in a 12 foot, 16 ga circuit at 12 V and 10 amps would be about .6V, so if you have a larger drop, your wiring is bad and needs fixing. .

In your example you only took into consideration the wire resistance. There are also the drops at each connection. Though small, they do add up. There is the connection to the battery, a connection to the fuse block, two connections for the fuse itself (we all have experienced the problems caused by dirty fuse connections ), the headlight switch connections, the dimmer switch connections and finally the headlight connections. By re-routing the bulk of the current through larger wire, less connections, and relays you can have horrible wiring and connections to the relay trigger, and still have excellent lights. As long as the trigger voltage does not dip below the relay pull in voltage you are good.

I would guess that even in a brand new Cruiser there was at least that much drop, probably more. Even using that conservative figure the obtainable light output would be reduced by close to 20%... I'll take that improvement.

I noticed Mr. Stern is also selling you solutions to things that aren't a problem. Find me a guy that isn't selling something that says that factory engineers use wire that is too small.

It's not that they used a wire that is too small (that implies they made a mistake) they compromised and still had a vehicle that met the requirements of the day. As someone above mentioned, economics plays a huge role in manufacturing anything.

The point is you can improve the light output on the Cruiser by running the headlamps as close as possible to their rated voltage.

Better lightning is a good thing. Especially when you get older and your night vision deteriorates.

 

[Pin_Head]

The point is you can improve the light output on the Cruiser by running the headlamps as close as possible to their rated voltage.

Yes, you can, if you think it is important. I don't. If the wiring is good enough for Toyota, it is good enough for me.

You can also greatly improve the light output by using higher power bulbs (if this is legal in your state).

 

[joeyg1973]

All this about bad wires and shorts brings me back to what I said originally... just buy a new wiring harness and stop the patchwork...

As far as what engineers state should be used let's put this into perspective... there are things called tolerances so that the accountants do things the cheapest way possible. It's why no engine comes balanced and blueprinted, it is within accepted tolerances. If they built every care to blueprint specs, they would be ridiculously expensive.

It's not that hard... I picked up an 18 circuit painless for 200 bucks 2 years ago.

 

[bsmith123]

To wire or not to wire? That is the question

I'm not sure how many Lumens it would take to actually notice a difference. But I kinda see both points.

Also If you had used lights that are rated a higher wattage then yes you may need bigger wires to carry the load but that not being the issue then what matters is the actual state of your wiring.

voltage drop will depend on the resistance--- in other words as the resistance goes up you need a higher voltage to get the same output. (which is not practical). On old wiring loose connections, corrosion, dirt in switches etc all raise the resistance but by how much will vary. Ideally by design the resistance in your wires would be negligible with the circuit resistance coming from the lamp itself so even with old wiring you may be all right because the wiring is figured out to carry the load without heating-- not to provide a given resistance--the lamps do that.

So really you could shoot the circuit for resistance and figure out what loss you will have using OHMS law

Roughly speaking if your aged wire has doubled the overall circuit resistance your 100 watts could become 50 watts because you are dealing with a fixed voltage and a fixed resistance (P = E 2 / R).

Now the shade tree way to do this might be to run a hot wire test lead to one side and your oem wiring to the other and see how much difference it makes in practical terms. If you are happy with the amount of lighting then good to go.


This could be an issue of temperment---do you want to know you are getting the most optimized lighting possible (max Lumens)or are you okay just seeing if it is good enough for what you hoped for.


I think older wiring may still be up to the task in many cases because new lights are brighter without demanding more power or in some cases demanding less power than the OEM ones

 

[KY854RUN]

Their reason may have been to increase bulb life? Just as output goes down dramatically when voltage to the bulb is reduced, bulb life goes up.

Coolerman,

This is true only for the older conventional headlamps.

For the newer Halogen lamps (both sealed beam and replaceable bulbs), the higher voltage actually extends their bulb life. This info comes from the 4Crawler.com brighter headlights page. Yes, he too is trying to sell a fix for a problem.