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Datsun 1200 wiring is relatively uncomplicated.
WARNING: Wire colors can vary by year, model and country. Please double-check the wiring in your Datsun 1200 before connecting parts according to this article. You don't want to burn something up! Use a voltmeter or test light to confirm the circuit behavior.
Also see: Wiring Diagram
Contents |
Wire color codes
| B | Black |
| W | White |
| R | Red |
| Y | Yellow |
| G | Green |
| L | Blue |
BW - Black wire with White stripe
Battery & Main Wiring
Battery has two wires, of course:
- Positive (+). Stock cable is RED. This connects directly to the starter's large connector. A smaller wire runs bout six inches from the terminal to the Fusible Link. See below.
- Negative (-, aka earth/ground). Stock cable is BLACK with Yellow stripe. It connects directly to the engine block at the oil pump. The engine end of this cable also has a smaller black wire. This is the main body ground and connects to the body at the Horn bolt
Main Wiring
There are three important main wires:
- Main ground wire (big battery cable). This bolts to the engine timing cover
- Body ground wire. This goes from the engine end of the Negative battery cable to the body. It's bolted down at the horn bolt. Without this weird problems can happen.
- Red wire at battery '+' terminal. This connects to the Fusible Link ("Main Fuse") about six inches from the battery
WARNING: Do not replace fusible link with a solid wire, or you risk burning up the entire wiring system ... If the fuse blows, figure out why before replacing it. Was there a short in the system, or did it simply overheat due to corroded contacts?
Fusible Link
Use a "FUL 0.5mm2" or better fuse-link. This goes between the battery and the main wiring harness (which also feeds the Alternator output "A" terminal)
- Part Number 25442-H2500
Fuse Box
In addition to the main fuse wire in the engine compartment, there is a main fuse box under the dashboard.
See main article: Fuse Box
Improvements
- Relocating battery to back of car. Advantages:
- Make room in engine compartment
- Balance weight of car
- 1200s are nose-heavy, so moving the 28-40 lb battery to the back helps. You need heavy-gauge cable, larger than stock due to the long lenght. Buy a kit with a sealed box, so fumes don't enter car
- Installing a modern new-fangled ground wire "System". There are two opinions:
AFRacer:
The grounding wire kits that people are putting on newer cars DO help out, and in many cases add power! I was a nonbeliever at first until I saw them used and they did add power and when I tore apart my 180SX I understood why it would add power. There are LOTS of electrical parts on newer cars, especially with EFI and distributorless ignitions ...
read moreddgonzal:
You've seen the ads where you install many grounds wires all over the car, sometimes using 'gold' connectors. They don't add horsepower. Not even new cars use this. There are advantages: They do make troubleshooting extremly complex wiring (like in a Mercedes with 47 computers) easier. My advice is don't waste your money on this.[edit:] After reading AFRacer's report above, I wonder if the B110 simply needs a better ground wire. The unibody is a large conductor so there is no problem there, but the stock ground wire is 1) kinda small and 2) in a place where corrosion can cause problems. Try using a thicker wire, grounding the battery and engine to the unibody in a better way (use a thick wire and good connections).
</blockquote>
Ignition Switch
The ignition switch bolts to the back of the key cylinder. There is a rectangular wire connector attached to it.
Alternator & Regulator
Our Datsun B110 used -- as with most 1964-1974 cars -- an Alternator with external Voltage regulator.
Alternator Connections
| terminal | Color | Logical Connections |
| A (Alternator) | WR or W | * To Battery + terminal through Fusible Link * To Regulator "A" terminal (W wire) |
| F (Field) | WB | * To Regulator "F" terminal |
| N (neutral point) | Y | * To Regulator "N" terminal * To electric choke relay Y wire |
| E (Earth/ground) | B | * To body ground * To Regulator "E" terminal |
Regulator Connections
| terminal | Color | Logical Connections | |||||||||||||||||||||||||||||||||
| A (Alternator) | W | | F (Field) | WB | <li>To Alternator "F" terminal | N (nuetral point) | Y | <li>To Alternator "N" terminal
<li>To electric choke relay Y wire | E (Earth) | B | <li>To body ground
<li>To Alternator "E" terminal | IG (ignition) | WL (72: W?) | <li>To fuse box "M" terminal (fused through to IG terminal of ignition switch) | L (Light) | WR | <li>To dash light "IGN" ('72, '73) or "CHG" (1971) |
How the Alternator Dash Light WorksThe dash lamp is connected to IGN +. The other side goes to the "L" terminal of the external regulator.
Alternator UpgradeMany different Datsun alternators and alternators from other makes can easily be fitted to the Datsun 1200. See main article: Alternator Upgrades Clock
The clock has a third wire, which goes to the Red/Black wire hanging down from the harness. This is the constant-Hot wire. If you wire to IGN, it only runs when the key is on :-)
HeadlightsSee Headlight Wiring Running Lights, Turn Signals, etcSee Lamp Wiring TachometerThere are two popular kinds of tachometers, using different wiring
Factory TachometerThe factory Datsun 1200 tachometer is wired differently than most tachos.
Datsun 620 TachometerThe tachometer from a Datsun 620 pickup fits exactly into a 1200. The colors and font are more like the PB110 or late model ute. Wiring is different. The 620 tachometer is triggered by voltage from the negative side of coil.
Aftermarket TachometerMost non-Datsun tachometers have four connections:
Ignition Coil & DistributorThe stock 1200 coil for 1971 and 1972 -- as with nearly all pre-electronic ignition systems -- uses a Ballast resistor to drop the voltage supplied to the coil. NOTE: The 1973 Wiring Diagram doesn't show a resistor, but it definitely has one.
Ballast resistor on right-side Strut tower (left side of photo)
Starter MotorStarter just has two wires: <li>Big RED wire: battery '+' terminal <li>Small BY wire: 'S' terminal of ignition switch. On automatic cars, this goes through the "Nuetral Switch" (inhibitor).
Choke And CarburetorSee: Interior LampsHere's the kinds of smaller lights (other than the headlights) that a Datsun 1200 uses.
Instrument Panel
SpeedometerThe speedometer has a light for use at night. See the lamp section.
1972 Facelift speedometer has special switch:
Ute Amplifier Speed SwitchAmplifier for B120 ute Throttle Opener Assembly (see Emission Controls). It's only fitted to the Manual Transmission models.
Switch has three wires. It looks as if, from these photos:
Double-check before using. USA Amplifier Speed SwitchUSA model from 0772 use an amplifier speed switch.
Cluster GaugesThe cluster gauge contains:
Fuel GaugeBack at the Fuel tank, there is a single Yellow (Y) wire on the sender.
The sender is grounded through the tank body.
Troubleshooting Fuel GaugeA non-working Fuel gauge is usually one of three things:
Dash LightsThese dash lights should light up when you turn the key to ON, before you start the car:
Both should go out as soon as the engine is started.
Troubleshooting Oil LightThe sensor for the Oil pressure lamp is on the fuel pump just above the oil filter (left side of A-series engine): This pump has a T-connector added. The original oil pressure sensor is the spade connector pointing down. A fitting for a mechanical oil pressure gauge is on the other end of the T. The sensor is an "idiot light". It simply connects the wire to ground when there is oil pressure. So before you start the engine (IGN key on), the Oil lamp bulb is connected to earth/ground through this switch and lights up. As soon as the engine starts and pressure builds, it disconnects the ground circuit so that lamp goes off.
Check the lamp again. If it still doesn't come on:
If that is not the problem:
This test is for functionality of the light. You don't need to start the engine to test this. If the light checks out OK, but there is no pressure or you suspect so, see Lubrication System Diagnoses. Troubleshooting Dash LightsAfter more than 30 years, these sometimes don't work. Could be a burnt-out bulb, corroded contact, or broken wire (turn signal indicators use wires).
 Cleaning dash light contacts |
