2011/02/18 23:54:02
wombat2509
Can anyone tell me where I can find the resistor in the fan circuit that makes the slow fan speed. I thought I had a 2 speed fan but having taken the heater box out I could be wrong. the wiring looks like a 2 speed but the box dosen't can do Pic's tomorrow if helpfull any one please.

John
2011/02/20 17:31:19
ronsmallford
There is indeed a resistor in the cicuit to drop the power to provide the two speeds. Follow the green and silver wire from the switch and it will plug into the resister and then onto the green and silver wire that goes into the fan. The other wire from the switch should be a green and yellow which provides the fast speed. The feed coming out of the motor is white which plugs into the cicuit that feeds the stop lights. I haven't actualy spotted a resistor as such because the car Im looking at has a bit missing. The resistor can simply be a length of resistor wire. (like the pink resistor wire that goes from the tacho to the ign. coil to provide 6-8 volts.) Hope this helps.
2011/02/20 22:01:22
oldcapriman
Hi Wombat
I like the colour of your car.
I had a similar problem when I was doing my car. I found that nearly every heater box was different.
Part 14 of my blog at http://my70fordcapri.blogspot.com/
might be of some use.
2011/02/21 00:36:47
wombat2509
Thanks for the reply I have actually read your blog & found it to contain lots of helpfull tips & links particually liked the Bill McMonagle link. As you said my heater box is different it looks like it is made of fiberglass were the one in your car appears to be metal part of the fun I guess

John







P.S. ya gotta love that top right hand screw

2011/02/22 21:40:53
oldcapriman
John
In my big manual there is a small picture of a similar type heater to yours, I think! In your top picture, the resistor bar(again, I think) sits between those two lugs, the left hand side of yours is broken off. The metal bar sits on the case of the heater & the lugs are attached but your picture shows no sign of the resistor bar. I am not sure if this confuses things even more.
Ian
2011/02/22 23:31:46
wombat2509
I think I can see what you mean it looks like the lugs are mounted on a metal plate there is nothing like it on mine. I broke the other lug off when I disconnected the green wire it is pop riveted from the inside but there is nothing there it may be as Ron said a resistor wire I just went out and took a pic of the switch plug and connector as you can see the wires are joined together at the heater (it is the two wires with the single crimp connector)



thanks for all the help
2011/06/03 22:42:55
wombat2509
Just to update as some of this is not covered well or easy to find,
as oldcaprieman said there are different types of heater boxes this worked on mine also I am not an auto electrician.

As can be seen in the photo (previous post)the fan wires are joined together giving me a single speed fan from my 2 speed switch being me I wanted 2 speeds this was more simple than it seemed at the beginning.To do this I read some where (couldn't find it again) that i had to drop the voltage to 9 volts

Simply put a very helpful auto electrician (B.O.W. in Lismore N.S.W.) pulled out his calculator and told me that I needed a 3 ohm 5 watt ceramic coated resistor in the low speed circuit, these are easily obtained (Autobarn 44c). The auto electrician said that the ohms are not as important as the watts (must be 5 watts) I ended up with a 3.2 ohm one this makes a small variation to the speed. In the photo of the fan on the right side a clip can be seen on the leg supporting the fan the resistor is cliped in here to keep it in the air flow so it wont over heat.

Thanks to oldcapriman & ronsmallford for the replies they helped point me in the right direction.

hope this helps the next person

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