How To Wire Aeromotive's Fuel Pump Wiring Kit | Fox Body Mustangs

In this article, LMR takes a closer look at Aeromotive’s heavy duty fuel pump wiring kit as well as explains some basic setup information that way you have a better idea as to how this wiring kit is used in a Fox Body Mustang. If we take a closer look at the wiring harness you’ll immediately notice Aeromotive’s great attention to detail. Each wire is wrapped with a mesh wire loom and then secured with heavy duty heat shrink to ensure that the mesh loom doesn’t fray.

Now the big question here is why would I need this wiring harness? Well, with the higher amp draw from aftermarket fuel pumps such as Aeromotive’s 340lph pump, the factory wiring size is not sufficient enough to handle the amp draw which is why you see heavy duty 10ga. wire used in this harness. This wiring harness consists of the following:

• 30-amp weather resistant automotive relay
• 4-ft 10ga. red power wire with integrated 30-amp circuit breaker
• 1-ft 10ga. black ground wire
• 10-ft 16ga. trigger wire
• 18-ft 10ga. red and black wire for fuel pump power and ground
• (2) insulated butt connectors
• (2) ring terminals for a #10 stud
• (1) large ring terminal for a 3/8ths stud
• (12) 6-inch zip ties
• (3) self-tapping screws

Now just because they provide the accessories, feel free to use your own ring terminals or wire management components since a lot of us have different setups. So because of everyone’s personal expectations and unique setups, we like to categorize wiring as a “custom install”. Now what we mean by that, is that the placement of the relay and wiring is a case by case basis. Some of you will still have a pushrod and some will have a Coyote. Moving forward with the basic steps, we/re going to do our best to explain where each connection needs to be made and we'll be referencing Fox Body Mustangs.

Before you begin, make sure you have a strong understanding of electrical systems. If you don’t, we would highly recommend assistance from a knowledgeable friend or have a trustworthy local performance shop do this for you. Now let's get started!

1. You’ll want to lay out the harness and familiarize yourself with everything and then plan a method of attack of how you want to run the harness.



2. Per the Aeromotive instructions, you need to first find a suitable place to mount the supplied relay. They want the main power wire with a circuit breaker as close to the battery as possible for optimal circuit protection. Depending on your setup, this can connect to the battery itself, the battery side of the starter solenoid, the lug on the alternator, or if you have a Coyote swap; this wire can connect to the main power lug in the fuse box.



3. This wire can be cut to length if desired. If it is cut, make sure to wrap the end of the mesh loom with electrical tape or use your own heat shrink to prevent the end from fraying. Install the provided large ring terminal onto the red power wire.



4. Next, you need to find a suitable ground for the short, black ground wire. Wherever you ground it, make sure the ground is clean and free of paint, rust, or corrosion.



5. Now you need to run the (2), long 18-ft 10ga. fuel pump wires to the rear of the car. You can run these wires through the car or underneath so pick your poison. If you run these underneath the car, make sure they are free of moving parts, exhaust components, and road obstructions or debris. Don’t run these wires alongside the fuel lines.



6. Once you reach the rear of the car, cut the wires to length if applicable. Again, make sure you wrap or re-heat shrink the mesh loom. Depending on what fuel pump assembly is in your car, you’ll have the option to use the supplied ring terminals or butt connectors. The car we have in the shop today has an Aeromotive 340lph fuel pump assembly and utilizes studs as the attaching point for the pump. Make sure you connect the red wire with the positive stud and the black wire with the negative stud. Wiring this the wrong way will cause the fuel pump to run backward.



7. Now we need to wire the trigger wire on the Aeromotive relay. If you’re still utilizing factory Fox Body wiring with a pushrod engine, you can use the factory fuel pump wire as the trigger. Doing this will utilize the inertia switch which is highly recommended. In the event of a crash, the plunger in the inertia switch is released which kills power to the fuel pump.



8. The factory fuel pump relay is either under the driver’s seat if you have a 1986 to 1991 EFI car or near the mass air meter if you have a 1992 or 1993 car. Don’t get the fuel pump relay confused with the WOT shut-off relay for the a/c compressor if you have a 92 to 93 car as the relays are right next to each other.



9. 1986 to 1991 cars can utilize the factory fuel pump wire from the relay under the driver’s seat. This is typically a pink wire with a black tracer, but you can also confirm this with a multimeter. The fuel pump wire will show 12v at key on and then drop to 0. You can also confirm this by checking the wire at the fuel pump.



10. Cut the factory fuel pump wire and splice the Aeromotive trigger wire into the relay side wire. You’ll need to supply your own butt connectors, heat shrink, or solder for this. You can simply use a piece of heat shrink or electrical tape on the unused end of the factory fuel pump wire.



11. Now for 1992 and 1993 cars; you’ll need to run the Aeromotive 12v trigger wire to the rear of the car. If needed, this can be extended. Because of the circuit differences from the earlier cars, the inertia switch is wired after the relay on the later cars. Locate the factory fuel pump wiring at the rubber grommet on the passenger side of the spare tire well. This wire is pink with a black tracer. Cut the wire and connect the Aeromotive 12v trigger wire to the side of the factory wire that is running to the inertia switch.



12. Use a butt connector or solder and insulate the splice with heat shrink. The unused end can be wrapped with electrical tape or use heat shrink.



13. Now for those of you that have a Coyote setup and you’re not utilizing the factory wiring; you’ll need to either rewire the inertia switch or wire in an inertia switch. The 12v positive fuel pump wire from the Coyote controls pack will need to be connected to the input side of the switch and the 12v trigger wire from the Aeromotive harness will need to be connected to the output side of the switch.



14. Once all of the wiring is complete, make sure the harness is properly secured and then test the vehicle for proper fuel pump operation.

Alright. We know that was a lot of information. If it helps, watch the video a few more times to have a better understanding. Again, if this is something that you’re not comfortable with, please reach out to a professional. Other than that, if you’re comfortable with wiring, this one should be a breeze.