Lotus Elan

Heater motor types

PostPost by: William2 » Thu Jul 24, 2014 4:47 pm

I am slightly confused about heater fan motors fitted to Elans. I have just refurbished one to use on my S4 restoration which is pre fresh air vent type and has a 2 wire motor. Are some motors 3 wire type for the 2 different fan speeds? I have fitted a high wattage low ohmic resistor to the unit I have to give me a slower speed and have bench tested it. I guess my question is, were there two different solution to achieving 2 fan speeds? I realise my heater is probably from an S2 or S3 car as it doesn't have the holes for the eyeball vents.
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PostPost by: rgh0 » Thu Jul 24, 2014 9:09 pm

The 2 speed motors all achieved this with resistors as far as I am aware. Certainly this was the case in my 69 S4 and 73 Plus2. The resistor used in both of these was the same rectangulalr ceramic ballast resistor used in that time.

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PostPost by: TroonSprint » Thu Jul 24, 2014 9:42 pm

Yes, my '71 Sprint has a 2-speed fan with three wires and uses a resistor to achieve the lower speed. Strangely coloured wires - for example the earth wire is white. Most unusual.
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PostPost by: billwill » Fri Jul 25, 2014 10:24 am

The S2 wiring diagram in the service manual shows a 3-wire heater motor.
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PostPost by: RichardHawkins » Fri Jul 25, 2014 8:27 pm


My 1968 S4 Elan has heater control as described by Rohan.

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