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The Hitachi LR Alternator series uses the same T-connector but wiring is different. If you use this newer type in an early Datsun 1200 the external voltage regulator must be disconnected a minor wiring changes made.
Contents |
Overview
JAPAN Datsun 1200 starting in 1981 uses an internally-regulated Hitachi LR-135 alternator. North America Datsun starting 1978 also used 35A, 50A or 60A versions. All are wired the same way.
L - Lamp (stem of T) -> To dash 'CHG' Lamp S - Sense (head of T) -> to BAT+ via Fusible Link
Here is the factory wiring diagram portion:
Notice the I.C Alternator T-connector head is connected to BAT+ line(unswitched battery voltage). 1978 B210 is the same but wire colors differ.
1979-1982 B310 North America colors B - Black wire. Earth/Ground W - thick White wire. BAT+ via Fusible Link W - thin White wire in T-connector head. BAT+ via Fusible Link WR - White/Red in T-connector stem. To dash 'CHG' Lamp
Notice that the I.C Alternator T-connector head is connected to A/BAT terminal (unswitched battery voltage). The splice occurs in the wiring harness.
1978 B210 Colors B - Black wire. Earth/Ground WR - White/Red. BAT+ via Fusible Link Y - Yellow. T-connector head. BAT+ WB - White/Red. T-connector stem. To dash 'CHARGE' Lamp
Fitting To Early Datsuns
If you install an LR alternator with internal-regulator on a 1200 or other Datsun with FN type alternator:
- disconnect the voltage regulator
- On the B110 regulator harness that goes down to the engine, connect WB wire of connector to WR wire of connector:
- WR <--> WB
-
wiring jumper
- Logically, you are connecting the "L" (Lamp) of new alternator to "L" (Lamp) of the wiring harness which is connected to the IGN switch. Be sure to use the original Datsun 1200 wiring harnesses as the "L" wire color WR is a switched source in the harness. Only one jumper wire is needed.
Some prefer two wires, which works on a 1200, 1200 with auto-choke, and with other Datsuns:
- Jump W to Y wires
- Jump WR to WB wires
wiring diagram:
Store-bought version ($30) of jumper wire
You can buy one mail-order from Bprojects. Endo will take care of you, send an email to Bprojects.
Price: 5,250yen (about $52 USD)
Wiring Explanation
CAUTION: if you jump W to B it will spark, begin to melt and then blow the Fusible Link. Possibly too with other wire combos too depending on if the key is on or off. In any case it should not cause a fire if the Fuses and Fusible Link are all in place. Older Datsun 510 & 521 may not use a Fusible Link, so be sure to connect the right wires.
Voltage Regulator connector * White: battery feed * Yellow: Neutral (of original FN alternator) * White/Red: Lamp (dash CHG or IGN light) * White/Black: Field (of original FN alternator)
In the conversion:
- Yellow goes to S terminal of LS alternator, so jumper connects Sense to battery
- WB goes to L terminal of LS alternator, so jumper connects Lamp to dash lamp
You can double-check all this with a voltmeter.
The original 35A alternator should have FN terminals
The Internally Regulated alternator should have LS terminals (but same T-connector as FN types)
Automatic Choke
NOTE: If your Datsun was factory-equipped with Automatic Choke, a second jumper is needed at the choke relay connector.
Original Wiring Comparo
With a wiring harness for LT-series alternator the choke relay is Voltage switched (voltage provided by Alternator).
Alternator output will power the relay, activating the choke heater. See Alternator_Wiring#Automatic_Choke_Relay.
With a wiring harness for LR-series alternator, the choke relay is Ground/Earth switched (ground provided by Alternator).
Alternator will ground the relay, de-activating the choke heater.
FN: relay with normally on connection to choke
relay clicks when engine starts running
LS: relay with normally off connection to choke
relay clicks when you turn IGN on
Compatibility
The Choke Relay is wired oppositely different on LT-series and LR-series applications. The respective wiring harnesses and relays match. New harness uses 6-pin relay. Old harness uses 4-pin relay.
When swapping newer LS-type alternator into older FN-type vehicle, swap N and L lines with a jumper wire. Then the lamp and choke circuits will work as designed.
Troubleshooting
1. Check the Voltage at the alternator. Between the BAT terminal and the E terminal (earth/ground) there should be the same V as at the battery. If not, you got a wiring problem.
2. The S terminal should be 12V hot when key is turned to IGN
NOTE: on the B310 with this, S is hot all the time either way will work
3. The L terminal (Lamp) should be:
- 0V when key is turned OFF
- 12V (more or less) when key is turnd ON
Because the L terminal is the exciter, if your CHG lamp is burned out, the Hitachi LR won't charge.
Engine Won't Shut Off
If wired incorrectly, the engine will keep running when you turn the key off.
Regulator Still Plugged In
The FN wiring is different from LS wiring. So if you leave the external regulator still plugged in, the wires are incorrect.
It won't cause overcharging, since the LR is internally regulated.
L-S Lamp: stem of Tee Sense: head of Tee
F-N Field: stem of Tee Neutral: head of Tee
If the external regulator is left plugged in:
- the Neutral line of regulator will be connected to the Sense terminal
- the Field output of regulator will be connected to the Lamp input/output terminal