Wire color codes
The Datsun factory service manual uses a consistent set of single- and two-letter codes for wire colors. They're mostly intuitive but two are worth memorizing up front: L = Blue (not "light" — comes from the Japanese/German blau tradition), and on Datsun, black is always ground (the opposite of some American conventions).
Please treat every year-specific claim, resistance value, or pinout on this site as a starting point — not a substitute for the FSM for your specific car. Each page has a Sources & verification section at the bottom; please tell us when you find anything wrong.
Base colors
| Code | Color | Swatch | Notes |
|---|---|---|---|
W | White | Often a hot-all-the-time main feed | |
B | Black | Always ground on Datsun | |
R | Red | Often associated with lighting | |
L | Blue | From Lan/blau — not "light" | |
Y | Yellow | Charge lamp, ignition feed circuits | |
G | Green | Tail / parking, EFI signals | |
Br | Brown | Various — radio, accessories | |
Lg | Light Green | Turn signals, some signals | |
Or | Orange | Less common, varies by year | |
P | Pink | Various low-current signals | |
Gr / Gy | Gray | Notation varies; common for senders | |
Sb | Sky Blue (light blue) | Distinct from L (blue) | |
V | Violet | Rare, mostly EFI on later models |
Tracer notation
Two-color wires use a base color plus a tracer (a stripe). The FSM writes them as BASE/TRACER:
W/R— white wire with red tracer (the heavy charge cable)B/W— black wire with white tracer (ignition switch IG output)B/Y— black wire with yellow tracer (starter solenoid signal)R/W— red with white (headlight low beam)R/Y— red with yellow (headlight high beam)Y/B— yellow with black (fuel sender)
Some FSM print runs omit the slash — WR and W/R are the same wire. A few rare wires have two tracers (L/B/W = blue with black and white tracers) but these are uncommon on the S30.
Hold the wire under good light. The base color dominates; the tracer is a 1–2mm stripe running the length. Old wires often look uniformly faded; gently scrape a few millimeters of insulation with your fingernail to expose un-aged plastic underneath.
Common circuit colors
These conventions are consistent across most S30 model years, but always confirm against the FSM legend page for your specific year — Datsun did tweak between years.
| Circuit | Typical color |
|---|---|
| Battery + (always hot, post-fusible link) | W/R heavy |
| Ignition switch "IG" (run) | B/W |
| Ignition switch "ST" (start) | B/Y |
| Ignition switch "ACC" (accessory) | W/B on later cars |
| Coil + (run, after ballast) | B/W |
| Coil − (to distributor) | B |
Alternator L (charge lamp) | Y |
Alternator S (sense, IR alt) | W/B |
| Headlight low beam | R/W |
| Headlight high beam | R/Y |
| Tail / parking lamp | G |
| Brake (stop) lamps | G/W |
| Right turn signal | Lg |
| Left turn signal | Lg/B |
| Hazard flasher | G/Y |
| Horn | G/B |
| Fuel sender | Y/B |
| Temp sender (gauge) | Y/W |
| Oil pressure sender | Y/L or similar |
| EFI injector signal (280Z, bank A) | G/B |
| EFI injector signal (280Z, bank B) | G/Y |
| EFI relay output (+12V to ECU/injectors) | W/B |
| Ground (any return path) | B |
Gotchas
The same color, different jobs
B/W means "ignition switch IG output" in the front of the car, but in the rear harness B/W may be a brake light feed. Wire color code is consistent within a circuit but Datsun reused base colors across unrelated harnesses. Always trace.
Faded vs. dirty
Old wire insulation oxidizes. A wire that looks brown might actually be red, faded. Pull a fresh section into the light, or scrape a millimeter of insulation off to confirm.
JDM vs USDM differences
JDM Fairlady Z harnesses occasionally use slightly different conventions (e.g., for fender mirrors, rear fog, JDM-specific accessories). If your car is an import, your FSM and harness may not match an "American" 240Z reference.
Aftermarket re-wire
50 years of owners means many S30s have non-original splices. If the colors don't match the FSM at a given location, somebody's been there. Confirm with a meter, not the colors.
Don't trust the swatches on a screen
The colored swatches above are approximations. Real wire insulation can vary in shade between batches and especially after age and UV. Use the swatches to differentiate wires you're looking at, not to match a Pantone.
Sources & verification
Claims on this page should be cross-checked against:
- Nissan FSM — every BE chapter has a wire-color legend page; always start there for the year you're working on. Free PDF scans of the FSM circulate on community archives; current links are typically posted in active forum threads on classiczcars.com.
- Atlantic Z Car Club — redrawn / colorized diagrams using the same convention.
- classiczcars.com — "wire color" reference threads.
- s30.world / Parts & Tech — part history.
Spot something incorrect? Drop us a note.