The On Line Store Page 1 below. . . .

The Auto Cool Guy has a better way to control engine temperature.

We use Pulse Width Modulation of your fan to control its RPM. Our sensor monitors the radiator outflow temp and adjusts the fan RPM to keep the outflow at a constant 15 to 20 degrees BELOW the thermostat temp. This way, the thermostat can regulate engine temperature. Use a laser temp gun and put the red dot on the outflow area and on a black dull surface for good results as you adjust the BLACK knob. Avoid shinny chrome surface due to temp errors. Take your time and do not rush this setting. After you have made this adjustment, you should see ROCK SOLID engine temperature. You will notice speed and motor load will effect your fan RPM - see its working.

By the way, fans with Auto Cool controllers do not KICK ON and off, leave that to the brand X controllers. Please don't tell me your Auto Cool wont KICK on.

FEATURES AND CONTROLS:

Soft Start limits inrush current with pulse width when the controller is powered up. Inrush current is a brand X controller killer when starting a fan motor from a dead stop.

A/C FAN SPEED control has a small pot on the side of the controller. When 12 volts is applied to the A/C controller pin, use a small flat blade screw driver to set this fan speed. The radiator temperature control mode will over ride the A/C fan speed automatically. If not used not a problem.

FAIL SAFE: The fail safe mode turns the fan on full RPM. The FS mode is turned on by grounding the FS pin. Use a small switch from FS to ground. You can turn FS mode on or off any time.

COOL DOWN TIMER: When you turn off the IGNIITION, the fan will keep running for a period of time to cool down your radiator and then shuts down.

FAN BUZZ: The buzz is caused by the fan blade and the armature shaft not tight.

We have found the Mark VIII fan have been reported at no buzz fans.

Our HF-125 controller runs at 7Khz to prevent the buzz but may have a high frequency tone cured by a large filter cap you see below. If your fan is brushless, use our HF controller only. The fan will vibrate at low RPM with low frequency controllers.

START ENGINE: As the motor and radiator is getting warm to hot, the fan will start turning slowly and gain RPM as the temp rises. The RPM will hold at the point of regulation set by the black knob.

The Auto Cool Guy now has these special capacitors to cure the high frequency 7,000 Hz tone in you fan. One each is included with the purchase of the HF-125 controller.

Use these caps only with the HF-125 controller if your fan has the high frequency tone problem.

DIESEL RADIATOR TEMPERATURE CONTROL

One of our early customers made this Youtube on the HF-125. At first we had a Fail Safe issue but corrected it and any that had been sold. This 7 Khz controller is one of our fastest selling controllers. Video made 2-2021

Sensor Warning: If your radiator OUTFLOW port is plastic, do not use the Standard Brass sensor. It will not get true heat transferred to the sensor! This will result in very low or no fan RPM.

I made this video of the DX-150 - how it works on the bench. It has ten LEDS that show percent of pulse width.

US ARMY ORDINANCE:
CALLED UP FOR A TOUR IN SOUTH EAST ASIA AND ASSIGNED TO THE 295TH ORD. FROM HASTINGS & GRAND ISLAND, NEBRASKA
10-68 TO 10-69. MOS: SHIT BURNER AND AMMO SUPPLY LABOR. TOUR WAS IN CHU LIE, QUAN TRI CITY AND DA NANG.

The photo on the left is the Auto Cool Guy. Location was north of Quan Tri City just south of the DMZ. When we were out of our base camp we always carried our M16s and at least 8 clips of .223 ammo with 20 rounds in each clip.

The photo on the right was taken one night outside of our hooch in Da Nang. For some reason I loaded 35mm high speed slide film in my camera and had it mounted on a tripod ready to go that night. As we were drinking beer and such, all hell brook loose and the sirens went off. Then we heard one of our NCOs telling us to get into our bunker. We answered back to this NCO that we were busy drinking and taking war photos. With my camera and standard lens I shot this time laps photo of a Cobra gun shop spraying 7.62mm rounds on the Da Nang perimeter. In the morning all the MPs found was a dead water buffalo. So you see all the fun you can have in the Army!

We have been building pulse width modulated radiator temperature controllers right here in the USA starting in 2011. We design and build quality and what the customers want!

The HF-125 is our new high frequency controller that operates at 7,000 Hz. This is the controller you want if you are going to power a BRUSHLESS fan motor. It will also power any brush type motor. It will prevent fan BUZZ ound in some Asian fans.

However, the HF-125 may have a "TONE" with some fans. So we will include a filter capacitor to install across your fan if you discover this problem. If you have two fans, you will need to order a second filter fapacitor from our on line store.

The BUZZ is caused by the fan and the amature not being tight

and shows up with low frequency controllers. It will be real loud at low fan RPM.

Our HF-125 has soft start and the cool down timer. . Two large 1/4 inch brass studs for fan and ground power. The top and bottom of the HF-125 is made from 1/8 inch aluminum plate for a heavy duty heat sink. The top case in powder coated.

HF-125 7 KHz PWM CONTROLLER

$265.00

HF-125 7 KHz PWM CONTROLLER

See our return policy data sheet