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.