A/C - Heater fan controller

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Rod 2500S
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A/C - Heater fan controller

#1 Post by Rod 2500S » Sat Feb 01, 2020 3:20 am

Gday all
My car is an Australian built 1978 2500S. It is fitted with an integrated AC. I don't think there are too many of these around. However it has the usual two speed heater fan switch which uses large wire resistors to supply the low and high speed supply voltages. Ok in the day but easy to bring up to modern standards.
Interestingly it came with a simple form of climate control using a "Davies Craig"style thermostat identical to those used on radiator fan controls. the capillary tube with thermostat was poked into the central face level air vent from behind and the knob was fitted to the dash near the clock. adjusting the set temperature modulated the AC off and on according to cabin temperature. Simple but effective, so I've retained it.
Ok prebuilt speed controller modules are ridiculously cheap and easy to obtain see this link for the one I used.
https://www.aliexpress.com/item/3283273 ... 4c4dQkz2AP (not advocating this site in particular but they seem to provide a good service)
I fitted the unit to a fibreglass board with a relay and mounted it next to the existing fuse/relay board under the passenger footwell. The relay was used to take the switching load off the small variable resistor/switch (POT) which is not really designed to switch the fan load.
AC fan controller 2.JPG
The switch/speed controller POT is then mounted on the dash next to the clock and thermostat.
OK this is a fair amount of work but it transforms the way the fan works giving full speed control from stopped to flat out progressively as in modern cars.
AC fan controller 1.JPG
Have fun lads
Rod

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Llessur
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Re: A/C - Heater fan controller

#2 Post by Llessur » Fri Feb 07, 2020 12:09 am

I'm in Adelaide and have a 1977 2500S with AC (a Sanden system which I think has been installed since the car was new). It doesn't have the cabin thermostat though.

At present the system is not functional - the interior units blows air when switched on but the rest of the system is discharged and would most likely need a full overhaul to function properly again. My engine's out at the moment and I did toy with the idea of removing the system to free up space under the bonnet and to save weight, but in an ideal world I'll get it functioning again one day so I think I'll reinstall it as-is for now.

It would be interesting to see a couple of pictures of your compressor, condenser, interior unit etc to see how it compares to mine. There are some pics of mine in my blog posts: https://triumph2500blog.wordpress.com/
Adelaide, South Australia (ex-Brighton, UK)
1977 2500S - White

My 2500 blog: https://triumph2500blog.wordpress.com/

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Re: A/C - Heater fan controller

#3 Post by Rod 2500S » Sat Feb 08, 2020 5:37 am

Gday
your compressor mounts look different to mine as is the compressor.
see pics
good luck with the build
cheers
PS for some reason my pics are inverted
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ac1.JPG

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Re: A/C - Heater fan controller

#4 Post by Rod 2500S » Sat Feb 08, 2020 5:40 am

for whatever reason the site has decided to drop two pics off
hopefully here they are
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ac1.JPG
ac3.JPG

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Re: A/C - Heater fan controller

#5 Post by Rod 2500S » Sat Feb 08, 2020 5:42 am

try this no 3
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ac1.JPG

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Re: A/C - Heater fan controller

#6 Post by Rod 2500S » Sat Feb 08, 2020 5:43 am

Good grief its scrambled them again
try again
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ac1.JPG

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Re: A/C - Heater fan controller

#7 Post by Rod 2500S » Sat Feb 08, 2020 5:46 am

It wont send the third one
sorry lads

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