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Old 07-26-2017, 12:22 AM   #1
70c10guy
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Deciding on a fan switch!

Hi all, this is for my 93 c1500. Stock 350 with a 195* thermostat. I was wondering what temperature on/off I should run in my fan switch for my electric fans. Should I be looking into the 200 on/195 off or 195/185? Not really sure on how exactly the science works. I tried reading a few posts but it confused the heck out of me. Thanks in advance guys!
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Old 07-27-2017, 11:13 AM   #2
Marv D
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Re: Deciding on a fan switch!

I guess look at it this way...

With a 195 thermostat and a 195/1785 fan switch,, the fans will come on as the motor warms up, and never go off. Which honestly will likely be the case anyways so doesn't matter. Electric fans (even on a switch) simply are not as efficient at pulling heat out of the radiator as the stock STEEL fan and thermal clutch.
Just remember, a cheep fan will have rpm and cfm at the sacrifice of a HIGH amp draw. You over tax the electrical system to drive a couple of inefficient fans and you have accomplished little more than robbing power from peter to pay spal <grins>
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Old 07-29-2017, 07:03 PM   #3
speedygonzales
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There are several different ways to go

ANY fan is as good as the volume it PULLS not pushes.

My Perma-cool unit I installed bout 11 years ago is far and away better than the mechanical unit it replaced. I did so when I lifted the body because the radiator and fan do not align when the body is lifted. Nice to have a lot of space in between the engine and the radiator also.

I also like it because the controls are variable from 170 to 210

There a few tricks I learned over the years that will give longer trouble free service from electric fans.

But this jewel right here
https://www.summitracing.com/parts/prm-21276/overview/

is the heart of a reliable system. Mine has a temperature probe that pushes in the fins of the radiator. They are available with either probe or screw in switch.

I haven't researched if you could get a single fan unit capable of pulling enough volume to cool my truck effectively. So I don't know if a low current unit is available. The dual fan unit I have will pull occasionally close to 30 amps. I never had a problem with the original 105AMP alternator but when it developed bad bearings, I replaced it with a 140A power-master unit.

The new permacool units flow more CFM only draw 19 AMPs.

First rule is never EVER use these for large amounts of power
Like in a fuse holder.
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Old 07-31-2017, 11:23 AM   #4
Kudzupatch
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Re: Deciding on a fan switch!

Quote:
Originally Posted by 70c10guy View Post
...Should I be looking into the 200 on/195 off or 195/185? ...
200 on/195 off. If you thermostat is trying keep the temperature at 195 and your fan switch is on at 185 it would rarely, if ever turn off.
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