Begin by following S&B Tank instructions to drop the tank and remove the sending unit. Also, follow your lift pump installation instructions for setting up your lift pump but DO NOT MODIFY your stock sending unit or tank. You may find it easier to prepare the S&B fittings for your lift pump with it unmounted from the vehicle. WARNING: The S&B Sending Unit is optimized for aftermarket lift pumps set to 16-18 PSI, do exceed 20 psi on your lift pump!

With the stock sending unit removed from the tank, remove the electrical connector for the fuel level float by depressing the tab and pulling away from the flange.

Disconnect the other end of the wire harness from the pump portion of the stock fuel sending unit by depressing the tab. Also, remove the metal clip from the stock pump by using a pick on the middle tab of the clip to pull it back and pulling up on the clip.

Remove the fuel level card and float by CAREFULLY separating the 2 black snap in arms from the stock sending unit and pulling the card out. Using a flat head or pick can help separate the arms. Cut the zip ties securing the fuel float wiring harness without damaging the wires.

Install the fuel level card into the black piece of the S&B Sending unit, verifying it is firmly snapped in and cannot move (it fits the same way as it does on the stock Sending Unit). Also, wrap the resistor card wire around the large hose a few times so that it cannot tangle with the float (you can also use zip ties to secure them). Snap in the electrical connector into the flange of the S&B Sending Unit, making sure the connection is firm

Note: The connectors that were previously plugged into the pump of your sending unit will no longer be plugged into anything, they can be wrapped or zip tied with the other connector so that it doesn’t come loose. (Your FASS/Airdog do not use these connections)

Insert the S&B Sending Unit into your fuel tank. The center of the tab on the sending unit flange should line up with the arrow on the tank. Be careful to not damage the OEM float when putting it in the tank.

Secure the S&B sending unit into the tank. Make sure the locking ring is oriented as it was on the OEM Tank so the sending unit guard will install without interference. Hammer the locking ring clockwise.

For FASS pumps Only (Airdog pumps skip to step 11): 

You may find it easier to remove the pump from the vehicle for this and the next few steps if it is already mounted. Unscrew the ‘To Engine’ fitting and ‘Return’ hose (not the fitting) if they are already connected to your lift pump. 

For FASS Pumps Only:

Apply the supplied thread sealant to the NPTF, or the long side, of the supplied brass tee fitting and hand tighten. Use a ⅞” wrench for the last turn and angling the tee off towards the frame of the truck. Adjust this so that when installed in the vehicle, the tee-off has clearance with the vehicle.

For FASS Pumps Only

Press the supplied 3/8" JIC fitting into one end of the supplied 3/8" fuel line. Screw this onto the tee fitting, also connecting the FASS to engine and return lines as shown. (Do not cut the 3/8" hose yet).

For Airdog Pumps Only:

Cut the “To engine” line at the front of the lift pump and splice it with the supplied barbed tee fitting as pictured, also connecting the supplied 3/8" blue fuel hose. Make sure the splice is in a good position when installed on the vehicle (the tee off will be routed back towards the S&B Sending Unit Flange).

Use this diagram to help you with the next steps in connecting the fuel lines to your S&B Sending Unit. Wait until verifying the position of the tank relative to the vehicle before cutting to length and installing your quick connect fittings! There are four fuel quick connections and the electrical connection:

• The elbow quick connect bundy fitting (12mm) with a blue locking tab (Item 13 in exploded view) will be inserted into the 1/2" hose supplied with your FASS/Airdog and route from the fuel return port on your FASS/Airdog. It connects to the port shown in the top left of the diagram.
• The larger elbow quick connect bundy fitting (5/8") with a green locking tab (Item 14 in exploded view) will be used with the suction hose supplied with your FASS/Airdog. High flow FASS pumps come stock with a 5/8" fuel hose that fits directly with this large green tab fitting. It connects to the port on the top right of the diagram.
• If you have a lower flow FASS or an Airdog, you will need to adapt to your FASS/Airdog suction line using the supplied short 5/8" fuel hose and 5/8" to 1/2" brass barbed coupler (Items 10 and 8 in exploded view). Then you can use the largest quick connect fitting.
• The Engine/Factory return from the vehicle will be installed into the only elbow male bundy connection on the S&B Sending Unit Flange. Install the supplied fuel line extension (item 14 in Exploded View) if needed to reach between the sending unit and the fitting on the vehicle. It connects to the port on the bottom left of the diagram.
• The smallest elbow quick connect bundy fitting (3/8") with a green locking tab (Item 3 in exploded view) will be used on the smallest diameter and tallest male bundy connection on the S&B Sending Unit (bottom right of the diagram) and will route back to the tee at your FASS/Airdog.
• The electrical connector should snap into the S&B Sending Unit connection point the same way it does on the stock sending unit.

This final checklist is very important.
1. Make sure all quick connectors and electrical connectors are locked in.
2. Prime your lift pump according to your manufacturer’s instructions.
3. Check for leaks before reinstalling the tank according to S&B instructions.

If you have any questions, call or text us at 909.675.1313.