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Freedom Fill Auxiliary System Info


Note: If you have a ATTA made fuel tank, please call us at 1-800-773-3047 with your Model Number and Serial Number to receive a lower price.



More Gauge Pod Mounting Options Shown Below In the Freedom Fill Instructions

The Freedom Fill Auxiliary System is a complete installation kit for your new ATTA aluminum auxiliary diesel tank. This fuel system is designed for full size Ford, Dodge, and GM/Chevrolet diesel trucks.

The Freedom Fill Auxiliary System meets or exceeds all DOT, EPA, and VESC-22 regulations.

How it works

ATTA’s  Freedom Fill Auxiliary System is a computer controlled fuel system. The small computer module mounted under the dash, sense the level of the factory tank and the auxiliary tank. When the factory tank reaches approximately a half a tank, the computer box will turn on the auxiliary in-line fuel pump. This will then begin to transfer fuel from the auxiliary tank to the factory tank. When the factory tank reaches approximately three-quarters of a tank, the auxiliary in-line fuel pump will shut off. Whenever the auxiliary tank is transferring fuel, a small light on the switch will turn on indicating fuel is being transferred from the auxiliary tank to the factory tank. When the auxiliary tank is near empty, the in-line fuel pump will not turn on. The aluminum auxiliary tank will have its own 2” gauge so you know how much fuel is remaining in the auxiliary tank. If the factory fuel tank drops below a half a tank, then you know the auxiliary tank is empty. The Freedom Fill Auxiliary System has an on/off switch which allows you to deactivate power to the system.

The Freedom Fill Auxiliary System is designed to work with Ford, Dodge, or GM/Chevrolet full size diesel trucks. This is one of the easiest systems on the market to install to you truck. Anyone with basic mechanical skills can install this system themselves in a matter of 5 to 6 hours or better. ATTA, inc. does have an extensive installing dealer network, please contact us for a dealer near you.

The Freedom Fill Computer Box will be programed to match your specfic truck. During checkout, you will be asked to identify your make and model.

Freedom Fill Auxiliary System Includes

  • 1x Auxiliary Fuel Gauge/Rocker Switch Gauge Pod w/ Wire Harness
  • 1x Gauge/Switch Pod Mounting Arm
  • >1x Freedom Fill Computer Box & Wire Harness
  • 1x Auxiliary Tank Sending Unit & Wire Harness
  • 8’ of 3/8” & 5/16” Fuel Hose (for Supply and Return)
  • 3’ of 5/16” Fuel Hose (for Vent)
  • 1x Rotary Vain Fuel Pump (70 Gallon Per Hour)
  • Applicable wire connectors, nuts & bolts, and self tapping screws
  • >Installation Instructions
  • No Cutting of Factory Lines
  • No Switching Valves to Fail
  • Always Run Off Factory Fuel System
  • Meets or Exceeds DOT, EPA, and VESC-22 Regulations
  • Available for All ATTA Auxiliary Tanks
  • Will Not Impede/Restrict Factory Fuel System

Freedom Fill Auxiliary System Instructions

Having trouble with the Freedom Fill Auxiliary System? CLICK HERE to view our troubleshooting guide.

Freedom Fill Auxiliary System

Gauge & Switch Console



  • Read entire installation instruction prior to installation
  • Use proper eye protection during any installation.
  • Work in a well ventilated area.
  • Do not connect or disconnect any wires with ignition in the on position
  • Do not modify or substitute any component provided with installation kit.
  • Any questions regarding installation, please contact your dealer.
  • Warranty will be void if installation is not followed as per installation instructions.
  1. Note: Attach locking suction cup to console arm to mount on windshield. Clean surface area to insure proper seal of suction cup. Or remove suction cup to mount directly to dash. Run wires to the underside of the instrument cluster. Insure the wires will not interfere with any moving parts (IE: brake pedals, parking brake, etc.). It may be necessary to drill a hole for routing of wires.   (NOTE: When routing wires, it is not necessary to pull wires tight, give yourself some slack).


Gauge Pod shown mounted to windshield

Gauge Pod shown mounted below dash.

Gauge Pod shown mounted in Center Console

Gauge Pod in Glove Box
Gauge Pod Shown mounted inside Glove Box

  1. Place the Freedom Fill Controller Box under the instrument panel, (It may be necessary to remove the dash panel). This can be done by using two zip-ties to attach the controller to a factory harness or bracket. Insert the Controller harness to the Controller Box.


  1. Connect the GREEN wire from the Gauge & Switch Console and Controller Harness to chassis ground. This can be done by attaching a small eyelet to the wire and using a self-tapping screw to a chassis ground.


  1. See owner’s manual for location of either a spare fuse or upfitter fuse. Connect the RED wire off the switch to a 12 volt ignition power source. When using a factory fuse, tap into the cold side of fuse. The cold side is the side of the fuse with no power if fuse is blown. Note: Spare, Auxiliary, Upfitter or SEO (Special Equipment Option) fuses are not used in any factory system and should be used when adding any accessory part. Do not connect red wire to direct battery power. To add the 15 amp inline fuse to the red wire, cut the red wire and place one end of the wire inside the fuse holder and clamp that side down. Place the other side of the wire to the other side of the fuse holder and clamp down. Insure each side of the fuse holder is properly in the locked position. Insert the 15 amp fuse to the fuse holder at the end of the installation.

ffs-fuse-panel.jpg ffs-inline-fuse.jpg

Examples of 12 volt ignition power sources. (Examples only, due to variations in vehicles, see owner’s manual.)

2015 Chevrolet 2500HD = #30 fuse, SEO, 15 amp (Located on Driver Side Fuse Panel)

2014 Ford F350= #44 Fuse, Auxiliary (Located on the Passenger Side Fuse Panel)

2014 GMC Denali 2500HD= #51 fuse, SEO/ALC (SEO Upfitter Usage)

  1. Connect the BROWN wire from the Gauge & Switch Console to the BROWN wire on the controller harness. Connect the PURPLE wire from the Gauge & Switch Console to the PURPLE on the Controller Harness. Connect the short YELLOW wire from the Gauge & Switch Console to the YELLOW wire on the Controller Harness.
  2. Connect the ORANGE wire from the Gauge & Switch Console to the Factory dimmer switch wire.  This wire is used for the auxiliary gauge light. The wire can be found behind the factory dimmer switch.  It may be necessary to use a test light to determine the proper wire. (See owners manual)(Use the supplied splice to tie the orange wire to the factory dimmer switch wire).
  3. Route the remaining wires (White, Black, Blue, and the long Yellow) through the fire wall and route the wires along the frame rail. Insure the wires do not come in contact with any moving parts. Use a small grommet or use a rubber boot when routing wires through firewall to insure wires will not chaff and create a short.
  4. Apply a gasket sealer to both sides of the gasket of the Sending unit. Install the Sending Unit Assembly to the tank using self-tapping screws. DO NOT BEND FLOAT ARM WHEN INSTALLING SENDING UNIT INTO THE TANK. Attach the Sending unit harness to the tank. The Yellow wire attaches to the center post of the Sending unit. The Green wire attaches under any of the self-tapping screws.
  5. Connect the 3/8” hose to the 3/8” supply port/check valve on the Sending Unit using a green spring hose clamp. Connect the long 5/16” hose to the 5/16” blacknylon return port using a black spring hose clamp. Connect the short 5/16” hose to the 5/16” aluminum vent port using a black spring hose clamp. Inspect all hose clamps to insure proper seal.
  6. Remove the lock-bar from the auxiliary tank and throw away shipping screws. Center lock-bar in bed and drill a 3/8” hole approximately 2” from each end of the lock-bar through the lock-bar and truck bed, then place a 3/8” carriage bolt in each hole. Insure the auxiliary tank is placed on some sort of isolation mat. (Drop-In or Spray-In bed liners will work. Mud Flaps or a rubber mat will work also). Position and center the auxiliary tank in the truck bed. The front hold-down tabs of the tanks will slide under the lock-bar. Drill a 3/8” hole in the rear hold-down(s) of the tank and bed, and then place a bolt in the hole. Route the wires and hoses under the truck. Insure the hoses are properly tied and no sharp bend was created. Place one flat washer, one lock washer and one nut on each bolt. Tighten all bolts.
  7. (A) ONLY TRUCKS WITH INTERNAL FILL VENT LINES NEED TO FOLLOW THIS STEP, ALL OTHERS SKIP TO 11 B. Trucks with an internal fill vent line it will be necessary to use the push-in adapters (not included with kit) on the factory fill neck in place of the vent-line adapter. Disconnect the factory fill from the body of the truck. Pull the assembly down the underside of the truck to make it easier to work on and prevent metal shaving to fall into factory tank. Using a 19/32” drill bit (a 9/16” bit may used, only if the 19/32” cannot be found), drill two (2) holes into the metal portion of the factory fill neck. *Note: Insure that the holes will be on the side of the factory fill neck facing the engine side of the truck when it is bolted back to the factory position. Remove any shaving that may have been produced. Place a bead of gasket sealer around the ring of the rubber boot of the adaptor, (do not install the elbow at this time). Insert the rubber boot into the 19/32” hole of the factory fill neck. Insert the metal elbow into the rubber boot. Insure that it has a snug fit. Place one long cable-tie around each of the push-in adapters.

    (B) Locate the factory fill neck on the inboard side of the truck bed. The vent line adapter has both a 5/8” & ¾” step, the same vent line adapter will be used for both sizes.  (If it is a 5/8” vent line, place it upon the 5/8” portion (lower step) of the Vent-Line Adapter. If it is a 3/4" vent line, place it upon the 3/4" portion (upper step) of the Vent-Line Adapter.) Mark the factory vent line where the cut should be made, insuring that you will have enough factory vent hose to slide over the adapter. Cut a small section (approx. 1” or more) out of either the 5/8” or 3/4” factory vent line. Place a large hose clamp on each side of the cut section. Insert the vent-line adapter and tighten the #12/#10 hose clamps. NOTE: On some trucks with metal fill vent lines, it will be necessary to cut a portion of the metal tube and add the applicable rubber hose to install the Vent Line Adapter. Do not “kink” the vent hose. It does not matter whether the 3/8” fitting or the 5/16” fitting face the factory tank.

ffs-vla.jpg  ffs-vla.1.png


(Pictures below shows Factory Fill Neck removed from truck. Example Only. The Factory Fill Neck does not need to be removed for installation of the Vent Line Adapter.)

Vent Line Adapter Close-up  Vent Line Adapter Close-up  Vent Line Adapter Close-up

*Note: Vent Line Adaptor may differ than picture shown.

(Installer Tip: When cutting a metal fill vent line, place a magnet on the line to catch any metal shavings.)

**Warning: When mounting the Vent Line Adaptor, be sure that the position of the factory fill vent line, does not allow the line to retain fuel. For example, a low portion of the hose that will hold fuel and not allow air to escape when normally filling the factory tank. This will cause spit-backs for the station fuel nozzle. Any fuel in the line needs to drain to the factory tank.

  1. Mount the inline pump near the Vent-Line Adapter. NOTE: Mount the pump so the lowest portion of the pump will be above the bottom of the frame rail. Insure the fuel flow is going from the auxiliary tank (marked “IN” on pump) to the factory tank (marked “OUT” on pump). NOTE: Pump must be mounted in upward position, arrow must be up. Run the 3/8” supply hose & the 5/16” return hose to the Vent-Line Adapter Area. Attach the 3/8” supply hose to the inline pump. Place and tighten with a hose clamp. It will be necessary to cut the excess hose off. Attach the remaining portion of the 3/8” hose to the other side of the pump. Place and tighten with a hose clamp. Route the 3/8” hose to the Vent-Line Adapter and place upon the 3/8” port. Route the 5/16” hose to the Vent Line Adapter. Place and tighten with a hose clamp. ENSURE ALL HOSES ARE NOT KINKED OR BENT TO RESTRICT FUEL FLOW. Note: when installing the Vent Line Adapter to the factory fill vent line, ensure the vent line will not create a low spot where fuel will sit. This can cause fueling problems, when filling the factory tank.
  2. The WHITE wire that was run through the fire wall will connect to the positive (+) wire on the pump. The BLACK wire will connect to the negative (-) wire on the pump. (Note: Do not cross wires, or damage to the FTC controller will occur. Damage to FTC controller will not be covered by warranty.) Note: The negative wire of the Pump does NOT go to Chassis Ground.


  1. The BLUE wire will splice into the Factory Sending Unit Wire. To ensure proper reading, attach the blue wire as close to the top of the factory sending unit as possible. (Going from the inboard side of the factory tank, it is possible to feel the factory wiring harness. Pull the factory harness towards you to attach the BLUE wire to the factory sending unit wire).  

Purple-04-14 GM/Chevrolet

Blue w/ Purple Stripe 2015+ Gm/Chevrolet  

Yellow with purple stripe-2008-current Ford

Yellow with white stripe 88 to 07 Ford front tank

Blue with black stripe 03 to 05 Dodge

Blue with white stripe-98-02 & 06-Current Dodge)

(See owner’s manual due to variations of truck wiring ).

  1. The long YELLOW wire from the gauge & switch will connect to the YELLOW wire from the Auxiliary Tank. The GREEN wire from the auxiliary tank needs to be connected to chassis ground.

How the System Works

When the system is turned on, the Freedom Fill Controller box will sense when the factory tank is approximately at a half a tank, the controller box will then turn the auxiliary in-line pump on, filling the factory tank to approximately three-quarters of a tank. The light on the switch will turn on allowing you to know when the system is transferring fuel. When the factory tank reaches approximately three-quarters of a tank, the pump will then turn off. When the auxiliary tank is empty, the system will not turn on. If the factory tank goes below approximate one-half of a tank, you know the auxiliary tank is empty. When the switch is in the off position, the auxiliary gauge and computer will be off, and will not transfer fuel from the auxiliary tank to the factory tank.

When the truck or the system first turns on, the pump &light will turn on for approx 5 seconds, then turn off. If the factory tank needs fuel it will then turn back on and begin to transfer fuel. If the factory tank is above approx ½ a tank, the system will remain off until the factory tank reaches the appropriate level of approx ½ a tank. If the truck or Freedom Fill System is shut off during fuel transfer, it will not turn back on until the factory tank reaches approx half a tank.  

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Return warranty card within thirty (30) days of installation to activate your warranty.

Wire Diagram


Hose Diagram