Wiring

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Revision as of 06:22, 26 February 2009

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

Wire color codes

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

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  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?

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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

Improvements

1. 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

2. Installing a modern new-fangled ground wire "System". There are two opinions:

   AFRacer:

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   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 more

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   ddgonzal:

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   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).

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   </blockquote>

Ignition Switch

The ignition switch bolts to the back of the key cylinder.

Ignition Switch Comparison

Interchange

B310 has a larger-diameter switch with two mounting lugs. B110 is smaller with one mounting lug. I believe the middle one (the one with the wiring harness) is a B210 switch, and looks like it would plug into the B110 harness, but is wired differently. Beware! I think this is the B210 Auto harness, where the BY wire goes through the auto-trans shifter inhibit switch (can only start car when in Nuetral or Park).

The 1971 switch has four spade terminals. The 1972 and newer adds the "Accessory" position and so has five spade terminals.

TIP: On the back of the switch, each contact is marked ('S', 'IG', etc.). Double-check before replacing to ensure they are the same.

B110 & B210 North American Wiring

The switch in the picture with the wires has differently colored wires (WR, L, BL, BW, BY). From these colors and position, I think it is the same wiring as the B310 switch, just different colors.

Wiring Connections
Switch internal connections

\*Starting with 1974 automatic models and all newer, ACC is also hot while in the Start position.

Where do the wires go on a stock B110?

Alternator & Regulator

Our Datsun B110 used -- as with most 1964-1974 cars -- an Alternator with external Voltage regulator.

Alternator Connections

How the Alternator Dash Light Works

The dash lamp is connected to IGN +. The other side goes to the "L" terminal of the external regulator.

• When the alternator is not putting out current, the "L" terminal is at '-' voltage, so the dash light turns on
• Once the alternator starts putting out current, the "L" terminal is at + voltage, so the light turns off (both sides of the light are at +)

Alternator Upgrade

Many 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 :-)

Headlights

See Headlight Wiring

Running Lights, Turn Signals, etc

The lighting circuits generally use Green wires:

• G - IG-hot from Fuse Box
• GY - Brake lights (stop lamps)
• GL - running lights (parking lights)
• GB - R.H. Turn Signal + running lights
• GR - L.H. Turn Signal + running lights

Turn Signals: The T/S path is as follows: From the IG side of the Fuse Box through the 10A "M" terminal (G wire) to the Four-Way Flasher Switch (Hazard Switch). This switch is normally off and so routes power through G wire to T/S Flasher Unit. This means one side of the T/S Flasher is normally HOT -- but only if the key is ON. From the T/S Flasher unit the power goes to the T/S Switch on the column. In the center position of course the power stops here. But move the switch to right or left, and the power is fed to the Left or Right circuits to power all the exterior bulbs and the two dash bulbs. The T/S Flasher Unit causes the power to start/stop resulting in flashing.

• NILES Hazard flasher bolts to right side of column brace (G/L, G/W)

• NILES Turn Signal flasher bolts to left side of column brace
• W wire goes into steering column harness, up to the T/S switch
• G is the other wire

Front Side Marker lamp connector

Front Parking T/S Lamp connector

Dimmer Switch (in T/S & Light Switch unit on steering column)
(T/S section of switch listed here)

Brake lights

Brake lights (STOP lamps) -- thankfully -- are simply connected on the B110. At the rear light boxes, the GY wires connect to the main harness GY circuit. This is connected to the "Stop Lamp Switch" at the brake pedal. The other side of this switch (both are YG wires) is connected to Fuse Box GY wire ("H" terminal 15A always-hot). So brake lights work when key is off.

Instrument panel "Brake" lamp
The IP brake lamp is not related to the rear brake lamps. Instead it signals if the hand brake is on ("Parking Brake Switch"), or if the master cylinder brake light switch ("Brake System Switch") senses a pressure differential problem.

Rear combination Lamp Box

  <li>To Instrument panel GR wire 

  <li>To Instrument panel GR wire 

</table> \*The rear wiring harness has a ground wire that bolts to the right-side rear bumper hold-down bolt (inside the car).

Reverse Lights are simply connected. The Red wire connects to the reverse switch on the side of the transmission. This switch in turn is fed from the G wire at the fuse box ("M" terminal of fuse box -- 10A fuse). It's always in affect, regardless of the Light Switch position. In other words, the Reverse light should work even if the headlights or running lights are off.

License plate lamp(s) is simply connected to the rear-harness "tail" circuit (rear running lights -- GW wire). See above. But it is grounded locally, not through a harness wire.

Interior Dome Light has one side of the lamp (RL wire) always hot from the L wire of the fuse box. The switch has three positions: <li>Off <li>Auto (center) <li>On In the auto position, the light is grounded by the Door Switch (BR wire in a-pillar). Usually only the driver's side door has a switch. In the ON position, it is grounded through the ground wire in the headliner.

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

USA 1972 Owners manual (see pages 35 for fuse information): If a fuse needs to be replaced, refer to the specifications listed on the fuse box cover.

Fusible Link

• 25442-H1100 LINK-FUSIBLE,TYPE C replaced by 25442-H2500

Tachometer

There are two popular kinds of tachometers, using different wiring

• Induction wiring. There is no actual physical connection of the tachometer to the signal wires. This is what Datsun uses.
• Voltage signal wiring. The tachometer wire is connected to the '-' terminal of the coil (e.g. to the points). This is what most aftermarket tachometers use. Simply wire this in without changing/cutting the existing wiring.

Factory Tachometer

The factory Datsun 1200 tachometer is wired differently than most tachos.

• B - ground - to back of Instrument Cluster
• YR - IG power - to back of Instrument Cluster
• RG - lights (two lights, two wires. Not shown in photo above) to back of Instrument Cluster
• BW - signal loop - to BW wires in dash harness

The BW loop of wire is the current induction coil. The ends, logically speaking, go in between the IG terminal of the ignition switch and the single-terminal (non-coil) side of the Ballast Resistor. Note that all IG current goes through this wire, so connect it up in series using the factory connectors (even cars without tachometer have the wiring in place). This is a BW wire along the top of the instrument cluster, seen here inside the yellow circle:

Pull the wire apart at the connectors, and plug the BW loop from the tachometer into it.

Also in the photo above -- marked as #1 -- are three terminals on the back of the speedometer, just below the left turn signal indicator connector. From top to bottom:

1. Lights - RG connect to male spade connector
2. Ground - B connect to round flat slide-on connector
3. IG power - connect to round bullet connector

   This applies to the Round Gauge dash. The square type has only the Light connector, but a tach can be grounded to one of the gauge housing screws.

Factory Tachometer Wiring Diagram and discussion

LATE MODEL UTE
Reportedly, some newer utes do not have the tacho wiring in the harness. In that case, run two new wires from the coil + side back to the dash, connect to the tachometer. See Tacho not working WHY

IGN + --------tacho------ballast--coil +

Datsun 620 Tachometer

The 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 Tachometer

Most non-Datsun tachometers have four connections: <li>coil '-' . usually red or yellow wire <li>IG '+' (hot only when key is on) - usually red or white wire <li>ground - black wire <li>light - often blue wire

So where to connect the wires?

• You can connect IG, Ground and Lights to the three connectors on the back of the speedometer (see above in the Factory Tach section)
• There is no factory interior connection for the coil '-' signal. So you'll need to feed a wire through the firewall and connect it to the coil

Ignition Coil & Distributor

The 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.

The 1973 wiring diagram doesn't show a resistor.

</table> \*The coil is supplied full battery voltage during cranking. Hence "R" terminal on ignition switch supplies V+ to coil.

Ballast resistor on right-side Strut tower (left side of photo)
The resistor is just above the coil, and is a white ceramic thing about 2-1/2 inches long.

Starter Motor

Starter 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 Carburetor

See:

• Eletric Choke Wiring
• Anti-diesel valve

Interior Lamps

Here's the kinds of smaller lights (other than the headlights) that a Datsun 1200 uses.

Lights (click for larger size and Details)

FASTEN SEAT BELT lamp

Instrument Panel

Speedometer

The speedometer has a light for use at night. See the lamp section.

1972 Facelift speedometer has special switch:

Ute Amplifier Speed Switch

Amplifier for B120 ute Throttle Opener Assembly (see Emission Controls). It's only fitted to the Manual Transmission models.

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The speed detecting switch is part of the speedometer assembly and is installed in the speedometer. The amplifier prevents damage to the speed detecting switch which actuate the throttle opener only when the car speed is above 10km/h. Pub No. SM6E-EMC0A0, Page EC-11

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Switch has three wires. It looks as if, from these photos:

• Red: Ground ? fits on round-side connector
• Black: -- goes to Red wire coming out of top center of panel
• Green: Unknown

Double-check before using.

USA Amplifier Speed Switch

USA model from 0772 use an amplifier speed switch.

• 25035-H7000 ASSY-AMPLIFIER SPEED SWITCH

Cluster Gauges

The cluster gauge contains:

• Fuel Gauge (Petrol/Gas gauge)
• Water temperature gauge
• Oil pressure indicator lamp (see "Troubleshooting Oil Light" below)
• Indicators lamp (see "Troubleshooting Dash Lights" below)
  • High beam indicator lamp
  • Turn Signal indicator lamps
  • Brake failure lamp

The coolant/water temperature gauge incorporates a voltage regulator.

• If both the water and fuel gauges are off, suspect the regulator
• If only one gauge is incorrect, suspect a bad connection, usually at the sensor
  • Temp sensor at cylinder head (on right side of head, at the very front):

    

  • Fuel sensor at fuel tank

Dash Lights

These dash lights should light up when you turn the key to ON, before you start the car:

• Oil pressure lamp
• CHG lamp

Both should go out as soon as the engine is started.

These do NOT light up on the pre-start check:

• Brake lamp
• Beam/M.B. lamp

Troubleshooting Oil Light

The 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.

If the lamp never lights up (IGN key on, engine not started):

1. Be sure the wire at the oil pump is connected to the connector
2. Pull it off and then on again to ensue it is tightly connected. If it is not, you can slightly crimp it with pliers to make it fit better

Check the lamp again. If it still doesn't come on:

1. Reach behind the dash and twist the bulb out. If it is burnt out, replace it

If the light comes on (IGN key on, engine not started), but does not go *off* when the engine starts:

1. Be sure the wire at the oil pump is connected to the spade connector. If it is off and lying against the engine or body is has a natural earth/ground and so won't work correctly

If that is not the problem:

• Disconnect the wire at the pump. Place it where it doesn't touch metal. Test the light again (with IGN key on):
  • Light is off: replace the sensor. One from most any Datsun model will fit.
  • Light stays on: You've got an unusual problem with the wiring or dash gauge cluster

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 Lights

After 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).

Testing dash lights