Does it make any sense to rewire the electric Air Conditioning fan to come on anytime the A/C is on rather than waiting for the 212 temp? How hard would that be to do?

 

It works for the D1. On the D2 it is supposed to come on in most AC use situations, unless you are at freeway speed. Like under 50 mph and more than 82F outside.

 

"Does it make any sense to rewire the electric fan to come on anytime the A/C is on rather than waiting for the 212 temp? How hard would that be to do?"

you could easily test your theory by powering your condenser fan of the same circuit as the compressor.

 

Would not the clutch cycle also turn fan on/off when it might be needed? The condenser will still have heat needing to be blown away once compressor turns off. Perhaps a method would be a relay/timer module. Drive it from the +12 that appears on the black with green on connector C0570-7, the voltage that runs the compressor. Timer would energize at once, connecting an earth ground to C0570-2, a green with white that is grounded by the ECU to engage the cooling fan relay. When AC compressor is cycled, timer would continue to maintain that ground until the time delay you selected was completed. It is tempting, as both wires are in the same connector on the bottom side of the underhood fusebox.

Or instead of a timer, an adjustable thermostat that you affix to the radiator with zip ties, etc.

I've always been a "fan" of a manual over-ride switch, you are pulling a trailer, you see the long stretch up the mountain coming, and as pilot in command you increase cooling.

 

yes; you could use a strap-on thermostat to control the fan. But for now I would just use the common ground to make the circuit, to see if it is a problem before I went all out rewiring the cooling fan. That is standard practice on a lot of vehicles when the ac is on the cooling fan comes on also.

 

You could just install a little toggle switch under the hood, winter and summer position. In summer, ground that relay line, and as soon as truck is cranked up fan starts.

 

The fan comes on any time your a/c compressor hits maximum head pressure which is all you need and it doesn't have to be at 212 degrees either.

 

Here it is.... I "assume" it's written by a land rover engineer... Definitely an engineer!! The pictures (23 of them) are very telling as well...
I should correct my earlier by saying this is covering the principles of the cooling system that is part of the disco- classic- defender and so forth. The basis of the report was to cover every step of the process in fitting the system to work for a different application where a "mysterious leak" had them baffled... (The mysterious leak on a British automobile!) is that only hilarious to me?????

http://www.conehead.org/Projects/Lan...ion%20tank.pdf
Here is that PDF file on the cooling system.. Kind of funny, very informative... Says for lr3 though I am not making the connection to what he's referring to really. Was published in 2013, done in 2012 if memory serves. Test bed looks to be a defender and is painted out like only an engineer would. They raided a tank from a mercedes 500 sel as a possible candidate... I grimaced when I noted he was dismayed it had a bung for a low coolant sender and indicated something to the effect that they'd need to fill it or plug it.. (Good grief!!). Anyways, this is applicable to at least the rr classics- disco 1 and disco 2 systems in the principle of its design etc.
on a side note, I had located an aluminum tank by similar means via amazon and endless surfing of the different tanks they sell. Found one almost perfect that uses traditional cap neck and I'm going to weld a bung in place for a float switch with a delay relay. Then it'll have low coolant warning (audible and visual) without going off intermittently while climbing etc. when its fashioned and tested out ill post the mod...
I'm almost sorry to say I was glued to this report like it was a short drama story with some epic ending that I already knew but needed to see play out..... Quite entertaining in a nerd ball way.... I knew my girlfriend was probably a keeper when she sat patiently in bed till all hours as I read aloud, laughing from time to time and cursing the bloke at key points...
Poor girl is a Prius driving attorney so why she'd give a hoot is only explainable in terms well above my pay grade.... enjoy..

 

With regards to the ac fan switching on when ac is active, my understanding is that it will come on when ac is on. So in a sense, it's a quick and easy measure to run the fan in a pinch. Though there are assumptions that the ac pressure switch is working etc. I found if the ac is not charged adequately then the fan won't cycle EVEN at the 212 deg threshold in one case. I'm assuming the ECM is needing pressure switch input as well as HVAC panel switch activation to punt the fan on. Again though, an electric fan set up with programmer will allow you to set cut in AND optionally set fan on when ac is commanded. Also a manual on switch as well as a manual off switch (water crossings) though I don't think that happens too often for most in real life.... At least not on purpose.. Haha
The appropriate variable controller will also cut fans in a reduced speed and then high speed as needed. Nice feature and amp draw is very manageable. Though I did do overkill with dual optimas and a 150 amp RR P38 alternator as I have a few extra loads throughout the vehicle..
Anyways, it's a great system if for no other reason than total control when married to the other components. The stock fan is easily put back on in a backwoods pinch in less than 60 seconds... That said, it never failed its original application over several years.

 

Thanks for posting the link (copied below), Bandit.

Mysterious leaks? Maybe this doc was written by the same engineers who built the Blackbird. Haha. But, then again, the SR-71's leaks were purposely planned by Air Force mechanical engineers, so that the Blackbird could attain optimal performance at maximum threshold for altitude and speed at extreme heat, pressure, and expansion. I'm not sure if any other aircraft, with or without leaks, can fly as high or fast as the Habu. Sorry to digress...

I'm looking forward to reading this 30 page, hilarious, short drama story. And, I'm not even bored!

http://www.conehead.org/Projects/Lan...ion%20tank.pdf
"Here is that PDF file on the cooling system.. Kind of funny, very informative..."