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jeremy93ls

How much wattage can stock headlight wiring support?

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It's been a while since I had to drive my '78 in the dark. The stock sealed beam headlights had me squinting the whole way to work. As soon as I got there, I ordered some 9" glass headlight housings with replaceable H4 55/60 watt bulbs. After installation and alignment, they're only a little better.

I've upgraded a '95 Tacoma similarly and bought 80/100 watt bulbs for it. It was a great improvement. Can the 280 wiring handle 80/100 watt H4 bulbs?

 

 

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Unless you have relays in the headlight circuit, the issue is that your voltage is too low. I have played around with different types of headlights. I have standard H4 lights at the moment, but the stock wiring is now controlling relays, and I have power for the lights going through the relays instead of the headlight switch. Just a couple of volts increase can make a world of difference in lighting. You'll find that you won't get much more light from the higher wattage bulbs until you address the voltage problem.

By the way, I hope that is a typo and you ordered 7" housings.

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Steve’s right on. You fixed the wrong thing first . Relays would make your headlights 10 times better . I upgraded to Cibie headlight lens , but also relays . Both are a great improvement , but relays are the biggest improvement and save you headlight combo switch and your fuse box too

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There might be someone who lives in about an hour away from you who knows about installing relays.

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☝️ This guy 🙂

Steve, you're a gentleman and a scholar.

Have LED bulbs not advanced enough to forgo adding relays and splicing into the wiring? I don't mind modifying the wiring, but can't help to think there's a better way these days. I was looking at this for my wife's ES350 since it didn't come with the HID lights, but haven't pulled the trigger yet. They carry an H4 version, too:
https://www.amazon.com/HIKARI-H7-Headlight-Brightness-Visibility/dp/B07XP1GG13/ref=sr_1_3_sspa?dchild=1&keywords=h7+led&qid=1602976309&s=automotive&sr=1-3-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyVkwyRURPV001UlIyJmVuY3J5cHRlZElkPUEwOTY2MTU4Mk5WUDI5RUZJWUkzUSZlbmNyeXB0ZWRBZElkPUEwOTgyMDg1Q09ETDc5QlBXVERMJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

 

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My stock wiring with LED bulbs in H4 lenses...

305fceb07d69fc16aff3c08e396c572b.jpg10d78390fa3cda5e2a522334c802d42b.jpg239dddce253d5c637d68e51d61528b2f.jpg

1/3 current of halogens, no relays yet, transformed night time driving, ‘nuff said!

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53 minutes ago, AK260 said:

My stock wiring with LED bulbs in H4 lenses...

305fceb07d69fc16aff3c08e396c572b.jpg10d78390fa3cda5e2a522334c802d42b.jpg239dddce253d5c637d68e51d61528b2f.jpg

1/3 current of halogens, no relays yet, transformed night time driving, ‘nuff said!

LED bulbs in H4 housings are next on my list to try. I have the bulbs. I have an extra set of H4 housings. I just have to move it up the priority list.

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1 hour ago, jeremy93ls said:

☝️ This guy 🙂

Steve, you're a gentleman and a scholar.

Have LED bulbs not advanced enough to forgo adding relays and splicing into the wiring? I don't mind modifying the wiring, but can't help to think there's a better way these days. I was looking at this for my wife's ES350 since it didn't come with the HID lights, but haven't pulled the trigger yet. They carry an H4 version, too:
https://www.amazon.com/HIKARI-H7-Headlight-Brightness-Visibility/dp/B07XP1GG13/ref=sr_1_3_sspa?dchild=1&keywords=h7+led&qid=1602976309&s=automotive&sr=1-3-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyVkwyRURPV001UlIyJmVuY3J5cHRlZElkPUEwOTY2MTU4Mk5WUDI5RUZJWUkzUSZlbmNyeXB0ZWRBZElkPUEwOTgyMDg1Q09ETDc5QlBXVERMJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

 

The thing is with LEDs is that you MUST have relays. I have not come across an LED headlight that can use 2 negative wires and 1 positive wire. 

I actually did come up with a "no splice" method of integrating the relays for the 72 and 73. I did a proof of concept on a friend's car. It is similar to what Dave Irwin (@Zs-ondabrain) did in the kits sold by MSA. I just get the headlight power from the fuse box. I just need to inspect the wiring in person for a 70 and 71 to design those because some things aren't lining up in the wiring diagrams.

Now it's a different story for the 260Z and 280Z. I have laid out a general design, but the challenge is that with the 260Z, they switched the dash to engine harness plugs to a Yazaki design that I haven't been able to track down. @Captain Obvioushelped me some with developing my ideas in another thread. What doesn't help is that the only source I can find for Yazaki connectors and terminals is Eastern Beaver in Japan. (http://easternbeaver.com/Main/Elec__Products/Connectors/Sealed/YPC/ypc.html) I would need to back out the wires from the connectors at the dash-to-engine harnesses and do my re-wiring there. It is feasible, but I haven't done it, yet.

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Fair comment, I’m not sure on the exact wiring differences between an early and later S30 but it worked out of the box on my ‘77.

I am very fussy and don’t like the headlight relay harnesses available and plan to make my own with relays inside the cabin. So LEDs was an easy win in the meanwhile (3 years ago!!). The light you see is with 11.8v at the headlight connector and 12.6v at the battery. They do get slightly brighter when you start the car, so even on LEDs the voltage matters, albeit marginally. The way forward is definitely relays and in in my books x5: one per side per beam, one for the rest of the lighting and in a discrete box under the dash near the heater motor.

That 0.8v drop is still quite a few Watts being dissipated in the car’s old electrics. In fact, I would wager that the wiring is still low impedance but it’s the connectors at the fuse box etc that need a good scrub! Which should be mandatory for us all given how much heat that can generate.

I looked very closely at those Yazu connectors but haven’t bought them yet: has anyone used these and happy with them?

Finally, if you do use the LEDs be sure to install them in the right orientation (it IS different to halogens, ask me how I know)! Halogens are up/down, LEDs are left/right. Most of them have a spinning head.

fb670b9a493f985c3705d0e2d00a0b42.jpg&key=8b7267f46de02d27a3db2b5a283742ae821c3e8b6c69239e92d2206e9d24a01e

Good luck chap.

Ps. Mine are Vanssi branded cheapos (about ($60) from China as i was very unsure and it was only ever meant to be an experiment / stop gap, but touch wood in three years and a lot of night driving they haven’t let me down ... yet!

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4 hours ago, AK260 said:

The way forward is definitely relays and in in my books x5: one per side per beam, one for the rest of the lighting and in a discrete box under the dash near the heater motor.

Agreed. I didn't put my relays in the interior (they are out in the engine compartment), but I used four relays. One per side per beam. Not only is it a more fault tolerant system, but it also minimizes the voltage drop in the switching system. Down sides are the obvious cost and complexity, but relays are cheap and the complexity is a once and done thing.

With the relays, I find my old original incandescent bulbs to be quite enjoyable on a dark road.

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Agreed. I didn't put my relays in the interior (they are out in the engine compartment), but I used four relays. One per side per beam. Not only is it a more fault tolerant system, but it also minimizes the voltage drop in the switching system. Down sides are the obvious cost and complexity, but relays are cheap and the complexity is a once and done thing.
With the relays, I find my old original incandescent bulbs to be quite enjoyable on a dark road.


Funny you should say that, my father in law’s TR4A and Volvo 123 Amazon are both relayed up and the light output with the 25% brighter bulbs is really quite impressive / plenty good enough. So I can see the Z lights working well if relayed.

Even though I run LEDs and will likely never go back, I have to admit that on a classic car, the warmer light of the incandescents “looks” better / far more age appropriate - but that statement is only valid if you can actually see the road well enough. ;) My philosophy for any improvement to the car is always a case of safety / driving experience first, originality second but the car has to “appear” as stock as possible where possible, until of course you give it the beans.

But to the OP’s original question, while the car’s own wiring is man enough to power the headlights, you can’t beat new wiring and connections through relays or the protection they offer for your stalk connectors.

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I'm skeptical about the validity of taking photos out the windshield showing how my headlights look, but if I get the chance, I will do that. I'm not sure it'll add any value without having a fixed "point of reference", but I'll give it a shot. The best thing would be to have your car next to mine and we could compare. We should figure out a way to make that happen some time.   :beer:

I did my 280Z relays using a hybrid method of old wiring and new wiring. I'm still utilizing the original fuses in their original location, but the switches on the steering column are only controlling relay current now, not the high headlight current. So for me, one of the nice things is that the two headlight fuses in the fuse block are still labeled correctly, one per side.

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@Captain Obvious In Your spare time😀.Would you be kind enough to create a rough schematic of your relay install. Also curious on where you located the relays. I’m waiting on other parts to arrive so this would be a good time to go ahead and do the headlight relay upgrade. No Hurry of course!!

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Adding onto this... on my 78 when I turn my headlights lights on the green/white wire going into my combo switch gets hot to the touch. Is that normal? If not where should I look to fix that?


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23 minutes ago, AZDatsun said:

Adding onto this... on my 78 when I turn my headlights lights on the green/white wire going into my combo switch gets hot to the touch. Is that normal? If not where should I look to fix that?


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That’s the sign that you need to do a relay upgrade before the combo-switch melts. 😳 burned my hand real good on my first car when I found that out the combo switch gets hot.

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I just looked at the schematic looks like green/white goes to the following but not the headlights..

Side markers
Turn signal/parking lights
All Gauges lights
Ashtray lamp
Radio light
Tail lights
License plate light
Cigarette lighter light
Glove box light
Hazard switch


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Beware.  Normal assumptions don't work.  My 70 Z's wiring demonstrated significant damage to the existing wiring close* to the headlight connectors (* up to 2" of contaminated/burned/almost smoked wire).  That damage means increased resistance.

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14 minutes ago, AZDatsun said:

I just looked at the schematic looks like green/white goes to the following but not the headlights..

Side markers
Turn signal/parking lights
All Gauges lights
Ashtray lamp
Radio light
Tail lights
License plate light
Cigarette lighter light
Glove box light
Hazard switch


Sent from my iPhone using Tapatalk

The running light solder joint fails also.  Too much heat, too many extreme heat cycles.  You can put a single relay after the combo switch to power the various lights and take the load off of the switch.  On my 76 it was a blue wire up under the dash.  Hard to get to.

I used a single relay on my headlight circuit also.  It's easy to do and will save the combo switch while you're pondering the more complex solutions.  Once that solder joint fails it tends to keep failing, I found.  I just patched it with new solder a few times but I think a proper desoldering and cleaning is the way to go if you want to run full current through it again.  It's a pain, avoid the broken solder joints if you can.

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I'm skeptical about the validity of taking photos out the windshield showing how my headlights look



Fair point - how about this for comparing LED v Old skool ....


c0d048419d24c4bbfd2296f6db794027.plist




I did my 280Z relays using a hybrid method of old wiring and new wiring. I'm still utilizing the original fuses in their original location, but the switches on the steering column are only controlling relay current now, not the high headlight current. So for me, one of the nice things is that the two headlight fuses in the fuse block are still labeled correctly, one per side.


I utterly love this idea and will copy you!!!

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11 hours ago, AZDatsun said:

Adding onto this... on my 78 when I turn my headlights lights on the green/white wire going into my combo switch gets hot to the touch. Is that normal? If not where should I look to fix that?


Sent from my iPhone using Tapatalk

Start by swapping out the incandescent bulbs for LEDs.

Here is some trivia I documented on this site, and no one seemed to notice. The bulb spec in the FSM calls out bulbs that appear to be NLA. Pretty much all of the BA-15 bulbs these days are 1156 and 1157. They are a slightly higher wattage (and more current draw) than the 1034, 1073,  and 67 bulbs called out in the 74-78 FSMs. The added current draw is not enough to blow the fuse, but it is enough to warm up all of the areas where some corrosion might have built up over 40+ years. Adding to that, IMHO, that circuit does not have the proper gauge wire. It's protected by a 20A fuse! In the control circuitry that my company manufactures, we never go above 10A fuses for 14AWG wire.

After you swap out for LEDs, you might need electronic flashers. I have been using this type for many years: https://www.amazon.com/dp/B07F1M9579

Also change out the parking light fuse from 20A to 10A. The current draw with LEDs is a small fraction of where it was before. The 10A fuse will protect the wiring better. (This is experience talking here.)

Here's the link to my post on current draw for the parking lights: 

 

Edited by SteveJ
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On 11/14/2020 at 6:41 PM, AK260 said:

My stock wiring with LED bulbs in H4 lenses...

305fceb07d69fc16aff3c08e396c572b.jpg10d78390fa3cda5e2a522334c802d42b.jpg239dddce253d5c637d68e51d61528b2f.jpg

1/3 current of halogens, no relays yet, transformed night time driving, ‘nuff said!

Yup. I did that too. Awesome upgrade from H4's.

So bright I had to make sure my headlights were aimed properly... 😎

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Well I figured out my green/white wire heating up with lights on issue. I noticed the heat really was starting at the plastic connector at the bottom of the steering wheel. I inspected it and there was a brown burn mark. I cut the green white wires on both sides of the connector and spliced in a new wire to connect them bypassing the wire harness connector. Now no more heat.. maybe it was a poor connection in the connector causing resistance. I am going to still change to LED though thank you !


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On ‎11‎/‎16‎/‎2020 at 2:10 PM, Yarb said:

@Captain Obvious In Your spare time😀.Would you be kind enough to create a rough schematic of your relay install. Also curious on where you located the relays.

Will do. I have a diagram around here somewhere. Some time ago I created a thread about it... I bet all the pics are dead because of photosucket.

In the meantime before I find the details... I had the whole engine compartment harness out of the car because I was doing other changes as well.  One of the other changes I made at the same time is I converted over to the internally regulated alternator and I put my headlight relays where the voltage regulator used to reside. Not sure what year you're working on, but on the 280's, the voltage regulator is on the back side of the relay bracket just forward of the battery. That's where I put my headlight relays.

I'll dig up my details and post them.

 

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