a bright idea.... DIY headlight harness

[Merlin93]

After all this discussion, tonight I finally MEASURED the voltage LOSS on my bone-stock headlights (H6024). 
Between the alternator  (+)  and the headlamp I lose 1.05 Volts.
Between the alternator case (-) and headlamp  I lose 0.85 Volts,
for a total of 1.9 Volts drop. The alternator outputs 14.3V and the headlamp sees only 12.4V. 

I'm gonna suggest that this may be about as good as a stocker gets, and only gets worse with age, corrosion, etc.
[My rig lived in the southern AZ desert for about 7 years, and has been mostly garaged in So. Cal, since then. ]
Seems to me we could/should do better.  There's some good info at: http://www.danielsternlighting.com/
with a good diagram:

The thing I noticed most is that he takes the +12V directly from the alternator, avoiding the voltage drop through the Suzuki harness.  This approach would get me 1 Volt more at the headlights -- that's a lot.  But you must fuse the wires, as shown in the diagram. Otherwise, you're asking for an electrical fire. I like my Zuk too much to let it burn up.

[t1h5ta3]

you might want to go back and re check the diagram and compare to the one i posted.
DS's diagram is corect for 99% of rigs out there, most use a switched +, the zuk uses a switched -.

if you have a 1v drop from the alt output and the bat, you have a wireing issue there as well....

[Merlin93]

you might want to go back and re check the diagram and compare to the one i posted.
DS's diagram is correct for 99% of rigs out there, most use a switched +, the zuk uses a switched -.
if you have a 1v drop from the alt output and the bat, you have a wiring issue there as well....

Perhaps I wasn't clear about the Daniel Stern diagram. It was not intended for a Zuk, although it might be adapted (the 85 and 86 terminals weren't wired quite right for a Zuk).  But it does contain some good info, as stated, specifically his use of the direct alternator connection which is the entire point. There really is a 1 volt drop between the OEM Samurai alternator output and the (+) terminal on the back of a headlamp when ON. This is not a defect, but a direct consequence of the roundabout routing that the OEM wiring takes from the battery to fuse block under the dash, and from there back to the headlamp(s). The return wiring (to ground) is rather lengthy as well, running from the headamp back to the switch on the steering column before being rounted to ground somewhere behind the dash in the cabin, several feet away from either the battery or the alternator. All this extra distance and wire adds to the voltage loss in getting the current from the alternator to the load (headlamp). The drop between the alternator and the battery is surely not zero, but it is not the biggest part of the total voltage drop, but actually the smallest! Not suprising, since it was designed to carry the full alternator charge current (35 or more Amps), while the headlight circuit carries about 10A for headlights.  The whole and only point is that maximizing the voltage at the headlamp means minimizing the loss in the wires. Relays can help, but smart design and short, direct wires are a necessity. 

[norzuki]

I have had these relays for a while now and was wondering if they would work?

the only difference is that it is a 5 terminal instead of a 4 terminal ....

it has a 87a right in the middle of the relay


0901 is the number on the relay




heres some pics

[Merlin93]

The relay pictured has a Normally Closed contact as well, which is not used in this application.( It has a slightly lower current-carrying rating, but headlights draw even less still and we won't be using it).  These are good for headlight relays -- just don't let the 87a tab come in contact with anything, 'cause it's hot (connected to the 30 tab), when the relay is off.

[norzuki]

ahhhhhhhhhhh yeah...........now all I need are the headlight sockets. I will be getting them here in a few.

[t1h5ta3]

just a minor little update... the lights came with 90/110w blue tinted bulbs, and yha they threw an ok amount of light. i personaly hate " cool white " light, esp in the rain etc. blue wavelength scatters so much...   any ways, i swaped the blue tinted high wattage bulbs out for some cheep off the shelf clear hella bulbs ( couldnt find any phillips or narva's around)   WOW!  i forgot how much tinted bulbs suck ! the 55w hella's threw alot more light down the road than the 90w ones did.   

so between the improved light output, and the improved color, its now much more plesant to drive in foul weather @ night.

let this be a reminder... silverstars suck, piaa's suck, tinted bulbs in general suck.  the only exception i make is " all weather" or " selective " bulbs with an actual dicronic coating to selectivly remove a narrow band of blue. the results is a goldish yellow output with exelent contrast and color rendition, not to be confused with a yellow tinted bulb.

[norzuki]

so help me out here cause..........yes I am redneck and ..........yes not to keen on electrical stuff.


on each "87" terminal ............. what does that wire connect to?

#1- new headlight plug

#2- old headlight harness

[Merlin93]

You can think of the terminals as input and output, 30 and 87 respectively.  30 is the "common" or fixed terminal of the relay providing +12V from the battery/alternator, and 87 is the moveable contact, which is pulled in when the coil is energized, supplying this +12V to the headlight terminal.   

Using  t1h5ta3's  illustration, the wires in one of the existing headlight sockets are used as a grounding trigger for the relay coil, and the output of each relay is connected to two new headlight sockets. 

Keep the wires from the source of power (battery/alternator) to the relays short and fat. Be _SURE_ to protect this new wiring with a fuse or fusible link. A 20A fuse (ATO/ATC) seems about right. [Note: Suzuki fuses the left and right headlights separately, with a 10A fuse in each of the separate circuits, so you only lose one headlight at a time (seems like a good idea to me)]. Do NOT neglect this important protection step -- one electrical fire could ruin your whole day.

[norzuki]

I figured it out when I started on wiring the lights and relays up. 

oh.......the connection at the relays are protected fo sho