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[Datsun 1200 encyclopedia]

Heater Wiring

From Datsun 1200 Club

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Categories: Body Electrical System | Heating And Ventilation Systems | Wiring

The Heater fan is powered by the 15A 'W' fuse in the Fuse Box. The 'W' fuse is for Wiper/Washer/Heater.



fuse box heater circuit
14924.jpgAlbum 14924


If the resistor is burnt out, the fan will only operate at High speed. You can replace it or, in a pinch, reconnect the two burnt ends using a small nut & bolt.

Heater Resistor (inside view) 27015-H3100 $12 USD
23995.jpgAlbum 23995

Look similar, possible interchange?
27015-H5000 B210, Late 620, F10 -1276 
27100-M0200 Early 620
27100-M3060 F10 0177-

Heater resistor (outside view)
23994.jpgAlbum 23994

174_5dc352ff4076f.jpgPost 493019 174_5dc3530aacf2e.jpgPost 493019 174_5dc353163bf37.jpgPost 493019

Regular Wiring

When IG is on, heater fan motor is always "Hot". But the motor is not grounded until the heater switch is pulled out.


Fan switch Position No. 1 is OFF
Fan switch Position No. 2 is low-speed via Resistor
Fan switch Position No. 3 is high-speed bypassing Resistor

Heater wire loom with B wire and Y, YR, wires:

(the blue wire is not part of the heater circuit)

fan switch

1972 USA

For 1972 USA models, the heater and switch operated differently. Now the motor fan is directly connected to Ground via B wire, and HOT is switched via a new type switch.


  • B: ground
  •  ?: High speed
  •  ?: Low speed


  • LW: 12V from Fuse Box "W" (Wiper/Washer/Heater) via LR wire
  •  ?: High speed
  •  ?: Low speed


Some 1200s have illuminated dashboard controls, like the B210.

1973 USA

The wiring is opposite of other 1200s and also includes to lamps for illumination.

When key is at IGN, fan switch is "Hot". Position #1 is OFF. Position #2 connects to the fan resistor (in the fan enclosure) for low-speed mode. Position #3 connects directly to the motor for high-speed operation.

USA 1973 wiring

PROBLEM: The wiring diagram does not show how the fan Black wire is earthed.

Fan (Heater)

  • B: Ground?
  • n: Low speed
  • n: high speed

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This page has been accessed 13,578 times. This page was last modified 22:24, 19 November 2019. Content is available under Datsun 1200 Club.