Thread: County AC Fan Speed

Originally Posted by goingbush

Manic, its going in the bin, you better take it even if you don't end up using it. Might just have a few weeks as we are all but packed and about to hit the road for 12 months, I've already packed the old loom that plugs into that, in the shipping container for storage, its buried in a bit far to retrieve.

do you have 12v on all your switch contacts, all the time, or just when the switch is pointing to that contact?

Ok if you don't mind sending it then I'll take it, I didnt want to take up your time unless I was 100% sure I'm going to use it. If you send me your paypal and postage cost I'll re-reimburse you.

There are three pins from the fan switch. When the switch is in the off position there is 0v on pin 1. On the high, medium and low positions pin 1 will be 12v, pins two and three are grounded depending on medium or high setting selected.

Hey guys,

I was reading this thread with a lot of interest as I had just taken my unit out of my '86 MoD Defender 110 for refurbishing. The inefficiency of the resistor is bothering me..

Originally Posted by goingbush

A lot of current gets chewed up by that little resistor which is why they burn out if the motor jams up or the airflow over the coil stops. Ditto - Electronic speed control, they use a thyristor / triac or similar mounted on a heatsink, which is why you burn your finger if you touch the heat sink.

obviously its all more efficient with the fan on high, seems stupid to introduce a red hot resistor into the air flow that your then going to try and cool down with the evaporator.

If I'm correct (not sure though) the speed of the motor is controlled by the amount of voltage it gets? In that case wouldn't it make much more sense to use a buck down (step-down) converter??

There are these cheap 10A usually around 0-30V converters from China...

Added benefit is a finer control of the blower, but ofcourse one would probably migrate from that 2-position slider to a knob or something.

By the way, does anyone know if the motor has brushes, or is brushless (if that even matters)..

Thanks guys!