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Auto Cool Quality


A lot of Auto Cool buyer's ask me why the our controller last for years when other controllers have early failures.  This may be because of the large heat sink and over rated transistors on Auto Cool controllers.   This keeps the internal heat to a minimum and avoids burning up transistors.  Also, relays are not used in switching fan current.


The Auto Cool controllers are big but its for a reason - its to absorb heat generated from switching fans with Pulse Width Modulation.  The Auto Cool controllers are made from 1/8 inch aluminum base plate for a robust heat sink.  Heat can distroy a transistor with thermal runaway if not controlled with a good heat sink.


Soft Start is used on all our controllers.  Its works when the controllers start a fan motor from a dead stop. 

The pulse width starts from very narrow and widens to give your fan motors a Soft Start.   This avoids huge

in-rush current that could even blow the diodes in your alternator!    If you intend to purchase the brand X controller for a lower price, see if it has soft start and relays that could fail over time!


There is no calibration or set up required, just install the controller system and drive.


The printed circuit boards inside our controllers are coated with a clear coating to protect the electronic circuits from moisture and FOD.  The design of the Auto Cool controllers are so that water will not be held internally.



The Auto Cool Guy found a real Russian Radiator fan controller!

Photo on the left is a new Russian controller.  The three other photos are the results of high fan pulse current burning out the PC board and blowing the transistors.


We received an email from Dmitriy in Kazakhstan. He was having problems with his Russian made radiator fan controller.   He was also having difficulty with the complex programing of this controller. 

Notice that this Russian controller used two small TO-220 transistors and it looks as if they are glued down to the top cover.  According to this manufacturer, this controller is rated at 420 watts.  Sounds like a good high number, right?   That's only 30 amps at 14 volts!

He made the right choice and purchased the NB-100 Auto Cool controller to replace this Russian controller.


Auto Cool Controllers use large solid state transistor to switch the DC fan motors with Pulse Width Modulation.   Transistors never arc like relays so solid state means reliability and a long life.



This "controller" is being sold on Ebay and on the web. They are actually AC electric hot water heater controllers being sold for automotive use.    Note the very long probe and the metal tube that could break to leave you without a working fan controller.   You may find one of these in a black plastic case.  The long probe could cause leaks in your radiator over time.



Hot water heater controllers

sold for automotive use???

This is a YOUTUBE video on a Derale PWM fan controller that had problems and was sent back to the vendor.  The Auto Cool Guy gets

a lot of calls and emails on the Derale controllers failures!


Notice that the Derale contollers have PVC wire extruding out of their chassis.  However the Auto Cool controllers have terminals and brass studs for high current connections.

You can avoid this type of cooling system break down by keeping your radiator temperature constant with the Auto Cool controller.   If your car has a controller that cycles on and off, this can cause pressure and temperature peaks that could lead to cooling system failures and you stranded on the highway!

We received an old Spal controller from Bill and a his email explaining the problems he encountered with the Spal and other PWM controllers.  


All of the other PWM controllers he purchased failed, with very poor  or

no customer service!


Read Bill's letter in the PDF below!

Milton has been receiving a lot of reports on Flex-A-Lite and Derale PWM controllers that are failing.   Customer service is another problem with these Brand X controllers that are not made in the United States.


The Auto Cool Guy has a proven track record of quality, long life and # one in customer service!    Go to the "Email" page on this web site and see what Auto Cool customers are saying about the Auto Cool Controllers.


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