Heater resistor?

Anyone know the specs? The one in the heater box, I need to replace mine.

No idea, other than 10 Ohms. Expensive, apparently.

Any idea how many watts? If I remember correctly there was a ceramic wirerwound resistor in there.

Power is I squared R or in this case, the current for the motor; 1 amp squared, that 1 x 1 x the resistor, 10 ohms which gives 10 watts.
Double it for safety and you get a 10 ohm 20 watt resistor, wire wound, ceramic.
Buy 2 x 22 ohm resistors and connect them in parallel making a 11 ohm 20 watt resistor.

http://www.maplin.co.uk/p/wirewound-10-watt-22-ohm-resistor-h22r

Cost 68 pence.

Motor current draw is 1 amp- presumably at full speed. Therefore the motor resistance is 12v / 1A = 12ohms (easy)
Motor resistance + resistor = 12+10=22 ohms total when the resistor is in the circuit at low speed.
12v / 22 ohms = 0.54A
P (resistor) = current^2 * R (resistor)= 0.52^2 * 10 = 2.98W

So a 20 watt resistor is slightly overkill, but will definitely work.

Nice one, thanks guys.

So what you guys are saying is you can solder in a new resistor from Maplins instead of trying to source the original part?

Are you sure a heater fan only pulls 1 amp, I would have put it closer to 10 amps.

doriz said:

So what you guys are saying is you can solder in a new resistor from Maplins instead of trying to source the original part?

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Yep. A resistor is a resistor. There's no such thing as a special Land Rover resistor. The only time you would need to look at a direct replacement for a part would be if there were any odd or strange mechanical items to consider such as shape or mounting methods.

Citizen Kane said:

Are you sure a heater fan only pulls 1 amp, I would have put it closer to 10 amps.

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The drawing does say it's a 1 amp motor, so apart from the initial starting (stall) current, one must assume that the normal running current is 1 amp.