Heater Motor Resistor

84ninety said:

Hi All!

I'm renovating my heater box.
I've just ordered a replacement motor as it was totally rusted up.
My control switches are all ok.
My resistor looks ok visually and I have put my meter on the resistor and its reading 4.5 ohms.
My question is - Does the 4.5 ohms sound about right? I can't find a documented value for that resistor!
Can anyone confirm?
Many thanks,
Paul
View attachment 280807

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dag019 said:

Have you seen the price of a replacement? I looked recently as part of rebuilding mine and decided it didn't matter what it looked like it was going back in and being reused rather than being replaced!

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Beneagles said:

Going by historical info:
https://www.landyzone.co.uk/land-rover/heater-resistor-utp1281.334764/
3.5 Ohms seems to be the "accepted" figure, but I don't think 4.5 will do any harm

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Beneagles said:

Curiously, this seems to be available at a very reasonable price these days:
https://www.johncraddockltd.co.uk/prc1716-resistor-for-heater-plug-up-to-1986.html

Don't remember seeing it when I bought replacement motor 6 weeks back

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tottot said:

Heater resistor in link above is for the glow plugs.

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tottot said:

Heater resistor in link above is for the glow plugs.

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miktdish said:

The resistor reduces the voltage to the motor, because the current draw is high you need quite a large resistor to dissapate the heat,

If you put no resistor in the circuit the fan runs at full speed, if you switch a resistor in the motor will run slower as the resistance increases.
The 'slow' speed fan can be changed to a 'medium/slow' by fitting a lower value resistor. A 2 Ohm 50W resistor (like this one https://www.ebay.co.uk/itm/183147416654) will give you a faster 'slow' speed.
These type of resistors also look like this ...https://store.brightcomponents.co.uk/product/2-ohm-aluminium-clad-power-resistor-50w-2r-50w/

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Beneagles said:

Ahhh...that may explain why I didn't find it when investigating heater electrics earlier. ty

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dag019 said:

Link heater resistor but only the resistor not the complete plate assembly which you can also buy but could not find any on a quick google. At that price I would be following the advice I was given during my heater box rebuild and if it doesn't work find a resistor with the correct rating and just mount it to the panel as it wont be seen once inside the blower box. Something similar to this but you would need to check the power rating of the motor etc (link)

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Beneagles said:

Curiously, this seems to be available at a very reasonable price these days:
https://www.johncraddockltd.co.uk/prc1716-resistor-for-heater-plug-up-to-1986.html

Don't remember seeing it when I bought replacement motor 6 weeks back

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