Every Lethal Performance and DivisionX return style fuel system ships with a dual or triple pump wiring harness, depending on how many pumps you are running. Those harnesses are plug and play and they work. The complaint we kept hearing was not that they failed, it was that they looked like a science experiment under the trunk lid.
The Box is the answer. It replaces that harness setup and moves every relay and fuse inside one compact, labeled enclosure. Same function, one tenth the visual chaos, and it tells you when something has gone wrong.
Three replaceable 30 amp fuses
LED power indication per pump
Plug and play to a DivisionX fuel hat
What The Box Is
A plug and play wiring solution for a dual or triple pump return style fuel system. It is available as an option on all of our 1999-up dual and triple pump return style systems, or on its own if you are building your own setup or upgrading an existing DivisionX system.
What's Included
- DivisionX The Box fuel pump controller
- 15 ft of 4 gauge power and ground wire
- 4 gauge ring terminals
- 7 ft of 12 gauge wire for 3 fuel pumps, with plug and play connector
- In-line fuse holder with 80 amp fuse, main power to the controller
- 15 ft wiring harness for pump trigger, Hobbs, or pressure switch
What's Inside
Everything that used to live exposed on the harness. Specifically:
- Three 40 amp relays. Not the small ones you find on competing products that were designed for lighting circuits. These are heavy duty 40 amp relays.
- Three replaceable 30 amp fuses, one per fuel pump. The lid comes off with four screws so you can get to them, and The Box will tell you when you have blown one.
What's on the Outside
The lid is labeled, and that label is the reference you will actually use when something needs diagnosing at 11pm.
One Side: Pump Connections
Three female connectors. The three connectors from the 7 ft 12 gauge harness plug in here, and the other end of that harness plugs into your DivisionX fuel hat for a plug and play connection.
The Other Side: Power and Indication
- Large gray connector, right side. The 4 gauge power wire from your main power source plugs in here and feeds the whole assembly.
- Three red LEDs, left side. This is the feature worth the money. Each LED illuminates when its corresponding pump has power. If one goes dark, you know exactly which pump lost power and can go straight to that fuse instead of guessing.
- Green female connector, left side. Your green and yellow trigger wires plug in here for the fuel pump trigger or Hobbs switch. Labeled: one pump on the left, two pumps on the right.
Wiring the Three Harnesses
Three harnesses come in the kit: power and ground, Box to fuel hat, and the pump trigger. Two are easy. One takes a decision.
1. Power and Ground
- Use the included 4 gauge ring terminals to wire up the power (red) and ground (black) cables.
- Wire both at the power distribution box main power and ground studs.
- Run them down the car, using the included in-line 80 amp fuse.
- Plug the large gray male connector into the large gray female connector on The Box.
2. The Box to Fuel Hat
The easy one. Plug the three smaller black male connectors into the three female connectors on the side of The Box, one per pump. The other end of that harness, with the single large connector, plugs directly into the top of the DivisionX fuel hat.
3. Fuel Pump Trigger
This one depends on how you want the system to behave. Two pumps means you use only the yellow wire. Three pumps means yellow and green.
To run the pumps any time the key is on, wire the yellow and green wires into the FPDM wire from your factory harness. That wire is in the factory harness plugged into your factory fuel hat. Pull back the loom behind the connector, find the right wire, cut it, and wire The Box's trigger wires in.
| Vehicle | FPDM wire color |
|---|---|
| 1999-2004 GT / Mach 1, 1999-2001 Cobra | Pink with black |
| 2003-2004 Cobra | Yellow with green |
| 2005-2009 Mustang GT / GT500 | White |
| 2010-2014 GT / GT500 | Violet with green tracer |
| 2011+ Mustang GT | Yellow with grey tracer |
Running a Pump on a Hobbs Switch
You may not want the third pump running all the time. A Hobbs or pressure switch triggers it only once the system sees boost, typically 5 psi. The pump stays wired in and functional, it just waits until it is needed.
How to Wire It
- Connect the Hobbs switch to a boost or vacuum source using the T-fitting and vacuum hose from the Hobbs kit.
- Connect The Box's yellow wire, for the first two pumps, and one wire from the Hobbs switch to the FPDM trigger wire.
- Connect the other Hobbs wire to The Box's green wire, for the third pump. This puts the switch in line between the FPDM trigger and that pump.
Once the switch sees its boost threshold it closes the loop and power flows to the pump. Want one pump continuous and the second on a pressure switch instead? Wire the green wire directly into the FPDM wire and run the Hobbs in line with the yellow.
Frequently Asked Questions
What does The Box actually replace?
The dual or triple pump wiring harness that ships with our return style fuel systems. Same function, with the relays and fuses relocated into one compact labeled enclosure.
Do I need The Box if my fuel system already works?
No. The existing harnesses work fine. The Box is for people who want a cleaner install and easier diagnosis, and it can be added to an existing DivisionX system.
What are the LEDs for?
Each of the three red LEDs shows power to its corresponding pump. If one goes out, you know which pump lost power and can go straight to that fuse instead of testing the whole system.
Which connectors do I use with only two pumps?
Pump 2 and Pump 3. Pump 1 is for the optional third pump.
Can I run one pump all the time and one on boost?
Yes. Wire the green wire directly to the FPDM trigger and run the Hobbs switch in line with the yellow wire.
What fuse does The Box use?
An 80 amp in-line fuse on the main power feed, included, plus three replaceable 30 amp fuses inside, one per pump.
Does The Box work with a non-DivisionX fuel system?
It is designed around the DivisionX fuel hat for the plug and play connection, but it is available on its own for custom setups. Call us and describe your system before ordering.
Keep Reading
Hide the Mess, Keep the Diagnosis
Heavy duty relays, serviceable fuses, and LEDs that tell you which pump quit. Available on its own or with any of our return style systems.
