Late DR30 Headlight Wiring .

[discopotato03]

Spent all yesterday afternoon trying to rewire the headlights because of voltage drop on both sides of the circuit . We opened the loom up from the lights to the fuse/relay box junction but the wires run back through the firewall . The wires themselves are puny and have two or three crimped joiners in the loom .

At this stage it was decided to make a new harness for the outer lights and trigger relays , powered directly from the battery , from the original nearside headlight wiring . We got all sorts of weird results ie one on not the other and high beams with the low beams on as well . I have a bad feeling all the answers may lie in the loom between the light control stalk and the firewall/fusebox .

Anyone attempted this before , Ghostrider once said his PNE has an aftermarket headlight harness in it . Pics would be lovely thanks Ghostrider if possible .

Cheers A .

[stagefumer11]

ok, ive done this myself on my hr30, did a whole trigger wiring setup, much better light output, we came across this problem to with the wrong set running, both on, you name it,

to solve it.

EARTH the relays thu the orginal light socket. so it earths thru the orginal relays.

it worked fine for mine, that was the only way it would work right

[discopotato03]

By this do you mean the relays switching earth ? Any help or diagrams greatly appreciated . By the way Im using 5mm wire which is overkill because I'm desperate for good lights with the iron mask front .

Cheers A .

[V8skylineMAN]

my old datto(1600/200b hybrid) had live healights, ie th power basically runs from battery to relay to lights to switch( or something).....but i dont recall how i did it as i made a complete new loom of my own design and requirements....so this post is basically me just rambling about the old days again

[discopotato03]

I think I need to get the stalk to trigger the new harness relays for best results . I don't want to earth the lights back through the original wiring as there is voltage drop on the earth as well as the positive side . I don't know if the inner lights will hack this but they've probably got voltage drop and need help as well .

Cheers A .

[stagefumer11]

yeah you are right, the orginal relays will be a switching eath. which is the only way it will work. we didnt notice anythng major in voltage drop when doing it this way.

We measured about a 50% rise in voltage in wiring up the secondary loom setup, and then installed 100/130 bulbs, and 100w high beams, which made a HUGE diffrence.

Its worth a shot, maybe only for a test, but it is up to you

[discopotato03]

I managed to borrow a Nissan R30 manual yesterday and found out how they did it . They use a system of two relays and the combination stalk .

When you turn the lights on the switch sends positive current from the fuse box to a common feed at the headlight bulbs , its a long way to the bulbs through tiddly wire with crimped joiners in the loom . The switch also sends positive current to relay no1 which is a switching relay (means connects one circuit or another not just off/on) which closes the contacts earthing out the low beam side of the H4 bulb . For high beam the switching relay is de energised and spring pressure closes the contacts on the alternate circuit which is the high beam earth return .

The inner high beam lights are really simple , permanent earth at the lights and positive current switched through relay no 2 . When relay 1 earths the high beam lights it also earths relay 2 so all high beam lights work together .

Where it all falls down is long runs of tiny wire (high resistance) with crimped joiners in the loom (high resistance joints) with all the positive current to the H4's carried by the 21 year old stalk switch (elderly high resistance switch) . The earth returns are also tiny high resistance with in loom crimp joints and tired 21 year old relays .

Relaying the common supply to the H4s is easy , one std relay switched by the stalk supply carrying positive battery (or alternator) current to the bulbs .

This fixes half the problem as the earths is the difficult bit . What I want to try is another two relays which when energised will connect the bulbs (high or low) earth return to the battery negative or chassis earth . I'll attempt to switch these

relays through the cars original high and low beam earth returns , the positive side of the relay switch permanently powered off the battery .

The inner high beams could be run off another relay carrying battery current and switched by their original power supply (relay 2) .

What this should give me is battery current and earth via 5mm wire , all close to the lights and switched by relays controlled by the cars standard high resistance 21 year old std system . All the dash lights should work because all the original circuits are still in use , just not carrying any loads .

Thats my theory and hope to have good lighting through the Iron Mask lights .

Cheers A .

[discopotato03]

So far got the power supply relayed . Need to run the H4 high and low beam earths back to the std relays (heavier wire) and give the relays themselves a decent body earth .

Only prob so far is that when turning lights off they stay on in the park light position . When turning the park lights on from off all is normal .

Cheers A .