Heater Fan Resistor Details

I’ve gotten several requests for the details of the fan resistor for the Range Rover Classic. The latest one came in from Patrick in France. Yes, that France, the one in Europe. He is the happy owner of a 1991 Classic Vogue SE with 4 doors and the 3.9 not catalysted engine in magnificent Beluga Black. Sorry no pictures.

His problem is the same as several of you had last winter that of trying to find a heater resistor to purchase. They are often difficult to find. He sent me a picture I posted the last time I replaced mine. Unfortunately for him the picture was not high enough resolution to make out the part numbers. You see, he is keen to make his own.

So I went out and removed mine and took down the details and took some photos.

Getting to it is relatively simple.
You remove the louver from the passenger side intake. It just takes a flat-head screw and a gentle touch. Remember your plastic bits are 20+ years old and are prone to breaking.

Once it’s out of the way remove the filter material. I have replaced mine with some air filter material I picked up from one of the big box stores. It’s cheap and sturdy.

filter

I had to drill out the rivet.  You can see it on the far side in the picture below. That was easy enough. Yours may also be riveted. Whatever, you need to be able to rivet it back or use a screw.

vent

And you have the resistor…simple.

resistor

The official part number for a resistor pack is PRC 8010.
The part numbers on the resistors are…
RIEDON452 UAL-50 .5Ω 5%
RIEDON452 UAL-50 1.5Ω 5%
RIEDON452 UAL-50 2.0Ω 5%

This one is an Atlantic British version. According to their website as of today March 10, 2015 they are in stock.
http://www.roverparts.com/Parts/PRC8010

This is cost prohibitive for Patrick due to the crappy exchange rate of dollars to euros, shipping, import tax, duty tax, it road in the back of a truck tax, more than one person handled the package fee, and five more taxes we’ve never even heard of I’m sure. SO, I also found them at Island 4×4 in the United Kingdom, currently in stock. Hopefully this won’t be so bad.
http://www.island-4×4.co.uk/heater-resistor-britpart-da4178resistor-p-7373.html

So if you are keen like Patrick you can source the resistors from the interwebs for just a few dollars and if you are handy with a soldering iron you can put your own together.

http://riedon.com/resistors/view/aluminum-housed-wirewound-resistors-ual

I wish you the best of luck getting a ready-made one or making one yourself.

Merci beaucoup Patrick for emailing.

UPDATE:

Patrick Ferrage emailed us a very nice drawing and schematic of the resistors and the wiring harness. This is top work and makes building one by hand a very simple matter. Once again thank you Patrick.

Drawing by Patrick Ferrage

Drawing by Patrick Ferrage

To the rest of you, thanks for reading and Happy Rovering.

4 thoughts on “Heater Fan Resistor Details

  • Hi Eric Stephens (Okierover),

    I’m working on a project and I have a blower motor from a Range Rover Classic 1987 and a blower motor resistor from 1988. So I want to connect the blower motor and resistor together with a 3 position switch. (so it works only on 1/2/3) not full power. But how does the resistor work? Where do I have to connect the wiring harness. I have exactly the same as on the drawing from Patrick Ferrage. Old one same color wiring.
    Where do these wires normally go in the car which color to where?
    Any idea? Sorry for bad english, I’m from the Netherlands.

    greetings René

    • The .5 resistor would be the fastest speed. The plug out to your switch would match the wires for the resistors excluding the .5 ohm. I wish I could be more help. Good luck.

    • Hi Rene & Eric,
      I can suggest to send you pictures of each connectors, switch and wires which are connected with heater fan.
      I have planned to refit my dashboard this weekend. What I can already say is that my heater fan motor has got 5 wires but only 2 are used. There is inside heating block nearby fan motor (on steel plate, left hand) another resistance not used on my classic.
      To answer your question working principle is simple : resistance is connected in sery with fan motor to create a voltage drop at motor connectors: the higher the resistance is, the lower the fan speed is. Full speed can only be achieved with direct supply, but i don’t think it’s the case in the car. I refurbished my fan and test it ( blocked in my vice) and speed with 12v supply was higher that one when fitted in car. I agree with Eric 0.5 ohm is the resistance to get full speed.
      Hope it will help, keep in touch for pictures.
      CU
      patrick.ferrage@gmail.com

I love to hear from my readers, leave a reply

%d bloggers like this: