HOW TO: headlight wiring upgrade

[2003z]

WHAT: Adding relays to headlight wiring circuit.

ADVANTAGE: Brighter light and safer. With full current coming off the alternator, your sealed beam headlights can be as bright as any new car (xenon excluded, but this will make a great foundation for a xenon upgrade) As stock, the entire headlight current runs through the fusebox, headlight switch, turnlight switch and speedometer high beam indicator. This draws a lot of current and can cause melt down if there is a problem.

DISADVANTAGE: Cuts stock harness, if you care.

 

HOW:

I did this to my last Z, although with a somewhat more complicated logic involving 3 relays. Refined it with the current Z. I converted my headlights today. Its very simple without a kit.

 

You need a relay holder, 2 relays, 2 fuses, and some wire.

 

With the stock setup, the Red wire powers the right headlight, the Red/Yellow powers the left. The Red/White is the ground for high beams and the Red/Black is the ground for low beams. With my system, the R powers the low beams and the RY powers the highbeams.

 

I mounted the relay holder on the fender well, just forward of the voltage regulator.

 

First unwrap the wiring harness in the vicinity of the VR.

Cut the Red, Red/Yellow, Red/White and Red/Black wires.

 

Wire as follows:

1st relay

86- R from cockpit

85- RB from cockpit

30- to alternator (inline fuse here)

87- RB to headlight

 

2nd relay

86- RY from cockpit

85- RW from cockpit

30- to alternator (inline fuse here)

87- RW to headlight

 

Take the R and RY from headlight, splice and ground to chassis.

 

Pure voltage straight from alternator and much brighter than stock, without the hassles of the harness.

[hat1324]

it seams your switching the polarity of the headlight correct?

The R/B and the R/W are your switches from the inside that give the lights ground.

your red and the R/Y are your switch power constants, allthough you could just run another positive wire from the alternator, letting you run less wire, allthough it would leave a loose wire..

 

Then your constant power from the alternator to the relay, goes to the stock ground for the low/high beams, then you ground the headlights, thus switching the polarity..

you could actually get away with just 1 fuse if you use the same ALT wire for both relays

ill deff be trying it

[Pop N Wood]

Or the HybridZ standard solution

 

http://alteredz.com/Headlight_Relay_pg1.htm

[Metallicar]

You have to give Victoria British some credit for now sourcing their kit for $29.95.

Part number 72-040 includes relays, wiring, and allows you to plug the existing headlight connectors into their provided female sockets. No cutting of the car's harness required.

[2003z]

You have to give Victoria British some credit for now sourcing their kit for $29.95.

Part number 72-040 includes relays' date=' wiring, and allows you to plug the existing headlight connectors into their provided female sockets. No cutting of the car's harness required.[/quote']The only problem with that is that according to the folks on classiczcar, it doesn't fit very well and has to be lengthened on some cars. Its actually made for toyotas, apparently.

[2003z]

it seams your switching the polarity of the headlight correct?

The R/B and the R/W are your switches from the inside that give the lights ground.

your red and the R/Y are your switch power constants' date=' allthough you could just run another positive wire from the alternator, letting you run less wire, allthough it would leave a loose wire..

 

Then your constant power from the alternator to the relay, goes to the stock ground for the low/high beams, then you ground the headlights, thus switching the polarity..

you could actually get away with just 1 fuse if you use the same ALT wire for both relays

ill deff be trying it[/quote']As it is in the standard system, the R/B and R/W provide the ground. I don't think I am reversing polarity, but I could be.

 

Could use one fuse, but I preferred to run them separately, so if a fuse or relay blew, I would still have a backup.

[hat1324]

you are, your using the Red and red/yellow as power constants, then giving power(from the alternator) to the original ground, then grounding the original power.. just reverse..

[2003z]

you are, your using the Red and red/yellow as power constants, then giving power(from the alternator) to the original ground, then grounding the original power.. just reverse..

yes, you are correct, but datsun (and most early japanese manufacturers) actually reversed them from the rest of the world. I just put it back

[hat1324]

yeah, I allways use power as my switch, and just ground it to the chassis....

[240playtoy]

I purchased this part.... yeah, it doesn't fit the stock harness of a 71 240z at all. granted the female ends that are to connect to the headlights would fit the headlight, it cannot be put into the headlight bucket w/o cutting the wiring and extending it. The ends for hooking to the headlight harness don't fit either. I ended up spending 1-2 hrs cutting, soldering and figuring out how to wire the thing properly. Ended up using the stock connectors from the harness and plugging the original headlight leads back into it. As for the reversing of the polarity, I wondered if that was why my old "high beams" were weaker than most cars lows. It wasn't a direct wire to wire ordeal, lots of testing w/ the multimeter to make sure my headlights lit up nice and bright.

[Cruez]

I actually am getting ready to do this. I've been eyeballing some H4 replacement housings on ebay, trying to narrow it down. Hopefully I don't end up with crap.

[240playtoy]

I got the Euro 7" 's from VB to replace the crap that put out less light on high as a small BBQ grill fire. Very nice, fit w/ no problem except the fact that my factory wiring was wrong for them. It was also wrong for the headlights that I was replacing.... thus the pitiful output. Good luck w/ your purchases and here's to blinding headlights

[TomoHawk]

entire headlight current runs through the fusebox, headlight switch, turnlight switch and speedometer high beam indicator.

Dude, check your wiring diagram. The high beam indicator light isn't part of the circuit for the headlight wiring itself. It only gets powered up from the high-beam side when you click the dimmer switch on.

 

the headlilghts are on a totally separate circuit from the turn signals too. They don't share any fuses or any of the wires.

 

thx

[2003z]

Dude' date=' check your wiring diagram. The high beam indicator light isn't part of the circuit for the headlight wiring itself. It only gets powered up from the high-beam side when you click the dimmer switch on.

 

the headlilghts are on a totally separate circuit from the turn signals too. They don't share any fuses or any of the wires.

 

thx[/quote']I'll double check it tomorrow, but I don't think I am mistaken. In either case, we will clear it up. thanks.