Power Distribution Module (PDM)

Installation & Setup Guide

Version: 1.03
Date: 03.23.2026

Important Compatibility Notice

The Aces EFI Power Distribution Module is intended for Aces EFI Gen 2 systems by default. Gen 2 systems are designed to use the PDM as the primary switched power-distribution device for the EFI system and related components.

Gen 1 systems are different. Gen 1 systems have relays wired into the main harness, while Gen 2 systems do not. Because of that, Gen 1 systems, or any system with relays already integrated into the harness, require a different wiring approach.

Do not wire a Gen 1 or relay-integrated harness exactly like a standard Gen 2 PDM installation unless the original relay architecture has been intentionally removed or redesigned.

If you are installing the PDM on a Gen 1 system, review the Gen 1/Relay-Integrated Harnesses section before making any connections.

1. Product Overview

The Aces EFI Power Distribution Module is a compact power-management solution designed to simplify wiring and centralize switched power distribution for EFI systems and related accessories.

The PDM distributes 12 V battery power across multiple controlled output channels and is designed to support key EFI-related circuits, such as:

• ECU main power
• Fuel pump power
• Cooling fan control
• Relay-fed accessory circuits
• Ignition-switched outputs
• Tachometer signal routing

By centralizing these functions in one module, the PDM helps reduce wiring clutter, improve serviceability, and create a cleaner, more organized installation.

The PDM uses IGBT transistor-based switching in place of conventional electromechanical relays, helping filter harmful transient voltage and provide improved protection for connected electronics.

2. Key Features

The Aces EFI PDM is designed to provide:

• Centralized power distribution for Aces EFI installations
• Independent switched control of major system circuits
• Fused output protection
• Clean ignition-switched outputs
• Simplified wiring with clearly identified terminals
• Support for fuel pump, fan, ECU main power, and relay-fed accessory circuits
• Compact mounting for easier installation in a wide range of vehicles

3. Supported Functions

The PDM is designed to manage and distribute power for the following common system functions:

• Main ECU power
• Fuel pump power
• Fan control
• Auxiliary relay-fed accessories
• Ignition-switched outputs
• Tachometer / POINT signal routing

The PDM is not intended to be used as an unrestricted universal power box. Every output channel has a defined current limit and must be used within its rated capacity.

4. Terminal Identification

Use the terminal names below when wiring the PDM.

Power Interface

Terminal	Function
VBAT	Main battery power input
GND	Main power ground

Control Inputs

Terminal	Function
VBAT	Main battery power input
GND	Main power ground
MRD	Main power control
RPUMP	Fuel pump control
RLY1	Relay 1 control (Fan 1)
RLY2	Relay 2 control (Fan 2)
RFAN	Fan control (AC fan)
IGNKEY	Ignition key signal control
POINT	Tachometer signal

Output Channels

Terminal	Function
VMAIN1	Main power output
VMAIN2	Main power output
VMAIN3	Main power output
VPUMP	Fuel pump power output
VRLY1	Relay power output
VRLY2	Relay power output
VFAN	Fan power output
IGNSW1	Ignition-switched output 1
IGNSW2	Ignition-switched output 2
IGNSW3	Ignition-switched output 3
POINT	Tachometer signal routing

Older Harness Revision Terminology

Some older wiring references may use alternate labels such as BAT+, BAT-, PUMP+, or IGNSW. In this manual, use the official PDM terminology above.

As a general reference:

• BAT+ corresponds to VBAT
• BAT- corresponds to GND
• PUMP+ corresponds to VPUMP
• Ignition switch input corresponds to IGNKEY
• IGNSW1, IGNSW2, and IGNSW3 are the switched outputs activated by IGNKEY

5. Specifications

Electrical Specifications

Parameter	Specification
System type	12 V vehicle system
Input voltage range	9 to 16 V
Maximum input current	60 A
Absolute maximum input voltage	22 V
Output on-state voltage drop	0.5 V or less at 10 A load
Switch response time	Less than 1 ms
Output efficiency	Greater than 96% at 10 A load

Environmental Specifications

Parameter	Specification
Operating temperature	-20°C to 105°C
Storage temperature	-20°C to 125°C

6. Output Ratings and Fuse Assignments

Use the chart below when assigning loads to the PDM.

Output Channel	Max Continuous Current	Fuse
VMAIN1	15 A	F4
VMAIN2	15 A	F3
VMAIN3	15 A	F3
VPUMP	15 A	F2
VRLY1	10 A	F1
VRLY2	10 A	F1
VFAN	10 A	F1
IGNSW1	1 A	Built-in self-resetting protection
IGNSW2	1 A	Built-in self-resetting protection
IGNSW3	1 A	Built-in self-resetting protection

Important Current Rules

• Each output channel must remain within its individual rated current limit.
• Channels that share a fuse must also remain within that fuse’s total combined capacity.
• Do not assume that because multiple outputs exist, they can all be loaded to their maximum value at the same time without checking shared fuse limits.

7. Control Logic

The PDM is an electronically switched module. Outputs are turned on by applying the correct signal to the corresponding control input. This means the PDM must receive the correct input signal before the related output will energize.

Control Input	Controlled Output	ON Condition	OFF Condition
MRD	VMAIN1 / VMAIN2 / VMAIN3	High level, recommended VBAT-3 V to VBAT	Low level, recommended 0 V to VBAT-5 V
RPUMP	VPUMP	High level, recommended VBAT-3 V to VBAT	Low level, recommended 0 V to VBAT-5 V
RLY1	VRLY1	High level, recommended VBAT-3 V to VBAT	Low level, recommended 0 V to VBAT-5 V
RLY2	VRLY2	High level, recommended VBAT-3 V to VBAT	Low level, recommended 0 V to VBAT-5 V
RFAN	VFAN	High level, recommended VBAT-3 V to VBAT	Low level, recommended 0 V to VBAT-5 V
IGNKEY	IGNSW1 / IGNSW2 / IGNSW3	High level, recommended 2.5 V to VBAT	Low level, recommended 0 V to 1.2 V

8. Before You Begin

Before installing the PDM:

• Disconnect the battery.
• Review the full wiring plan before making connections.
• Confirm whether the vehicle is using a Gen 2 system, a Gen 1 system, or a harness with relays already integrated.
• Identify which loads will be powered directly by the PDM and which functions are only control signals.
• Confirm the actual current draw of the fuel pump, fans, and any accessories before assigning them to a PDM output.

Mount the PDM in a dry, protected location away from direct heat, sharp edges, water intrusion, and moving components.

Whenever possible, mount the PDM close to the battery and ECU to minimize wire length and simplify routing.

Recommended Tools and Supplies

• Multimeter
• Wire crimpers and strippers
• Screwdrivers
• Heat-shrink tubing
• Electrical tape
• Electrical connectors
• Automotive-grade wire
• Proper grounding hardware
• Loom or abrasion protection as needed

9. Standard Installation Procedure for Gen 2 Systems

This is the default installation method for Gen 2 systems.

Step 1: Mounting the PDM

• Mount the PDM securely using the mounting holes provided.
• Choose a location that is dry, protected, and easy to service.
• Keep the unit away from exhaust heat, water exposure, and moving components.

Step 2: Connect Main Battery Power and Ground

• Connect “VBAT” to the battery positive.
• Connect “GND” to battery negative or to a verified chassis ground of equal electrical quality.

Keep both the power feed and the ground path short, direct, and appropriately sized for expected current.

Step 3: Connect Ignition Key Input

• Connect a true ignition-on source to “IGNKEY”.

This source should remain active during engine cranking. Do not use an accessory-only circuit that drops out during starting.

When IGNKEY is active, the PDM energizes:

• IGNSW1
• IGNSW2
• IGNSW3

These outputs provide clean switched power for supporting circuits.

Warning: Do not run ignition coils off of the PDM, or it will damage the system

Step 4: Connect ECU Main Power

• Use “VMAIN1”, “VMAIN2”, and/or “VMAIN3” for the ECU main power path as required by the system design.
• Use “MRD” as the main power control input for the VMAIN outputs.
• Follow the system wiring plan to determine which VMAIN outputs are used by the ECU and related circuits.

Step 5: Connect Fuel Pump Circuit

Use “VPUMP” as the fuel pump power output.

Use “RPUMP” as the fuel pump control input.

Verify actual fuel pump current draw before final connection. The fuel pump circuit must remain within the 15 A maximum rating of VPUMP.

Step 6: Connect Fan Circuits

Use “RLY1” and “RLY2” as control inputs for relay-fed fan stages or related switched circuits as required by the application.

Use “VRLY1” and “VRLY2” as the corresponding relay-power outputs.

Each of these outputs is limited to 10 A maximum, and both share fuse F1.

If a fan motor or fan stage exceeds the available PDM channel capacity, use the PDM output to trigger an appropriately rated external relay rather than powering the fan motor directly from the PDM.

Step 7: Connect Auxiliary/AC Fan Circuit

Use “RFAN” as the control input for the auxiliary fan circuit.

Use “VFAN” as the corresponding fan power output.

VFAN is limited to 10 A maximum.

Step 8: Connect Relay-Fed Accessories

Use “VRLY1” and “VRLY2” for controlled relay-fed accessories where needed.

These outputs are suitable for devices such as auxiliary pumps, secondary fans, or other switched accessories when used within their rated limits.

Step 9: Connect Tachometer/POINT Circuit

Use “POINT” for tachometer signal routing.

Treat the POINT circuit as a signal path only. It is not a load-power output.

10. Gen 1/Relay-Integrated Harnesses

This section applies to Gen 1 systems and any installation where relay logic is already built into the harness.

Why the Procedure Is Different

Gen 2 systems are designed to use the PDM as the primary switched power-distribution device.

Gen 1 systems already have relays wired into the main harness. In those systems, some harness wires may already act as relay triggers or relay-fed outputs rather than direct load-power circuits.

Because of that, a Gen 1 harness cannot simply be wired the same way as a Gen 2 harness.

Primary Rule

Do not wire a Gen 1 or relay-integrated harness exactly like a standard Gen 2 PDM installation unless the original relay architecture has been intentionally removed or redesigned.

Recommended Method for Most Gen 1 Installations

In most Gen 1 applications, the safest approach is to let the existing harness relays continue handling the final load switching while the PDM is used upstream as a cleaner power-distribution and controlled-feed device.

That means the PDM can be used to:

• provide clean, fused battery-fed power
• provide keyed switched outputs
• provide controlled feeds to relay-trigger or relay-fed accessory circuits

It should not be used to duplicate a switched output path that already exists in the harness.

What to Avoid

• Do not tie a PDM switched output directly into a circuit that is already receiving switched power from an existing harness relay.
• Do not feed a PDM output into the output side of an existing relay unless the circuit has been intentionally designed that way.
• Do not assume that a pump, fan, or ignition-labeled wire in a Gen 1 harness is always a direct load-power wire. It may only be a relay trigger.
• Do not double-switch the same circuit through both the original relay architecture and the PDM.

When a Full Conversion Is Acceptable

If the harness is being intentionally reworked so the PDM becomes the primary switching device, the original relay-fed output paths must first be removed, isolated, or bypassed correctly.

Only then should the final loads be reassigned to PDM outputs, and only if every circuit remains within the official output and fuse limits in this manual.

11. External Relay Guidance

An external relay may still be required in some applications.

Examples include:

• when a load exceeds the current capacity of the assigned PDM output
• when a fan circuit requires more current than the PDM can provide directly
• when a Gen 1 or hybrid installation still depends on conventional relay logic
• when the vehicle cannot maintain a stable keyed 12 V source during cranking in a non-PDM or hybrid setup

Relay Trigger Basics

Some relay-based systems use a positive trigger, where 12 V is applied to activate the relay.

Others use a negative trigger, where the relay has constant 12 V available and the switching side provides ground to activate it.

In relay-based fan setups, Fan 1 or Fan 2 may function as a negative-trigger relay signal rather than a direct high-current power output. Keep that in mind when integrating the PDM into older or relay-based systems.

Standard Automotive Relay Reference

Typical relay terminal functions are:

• Pin 30: fused battery power input
• Pin 87: output to accessory
• Pin 85: relay coil control side
• Pin 86: relay coil control side
• Pin 87A: normally closed terminal, often unused in these applications

12. Wiring Best Practices

For the most reliable installation:

• Keep battery and ground connections short and direct.
• Route high-current wiring and signal wiring cleanly and separately where practical.
• Protect wiring from abrasion, heat, and vibration.
• Verify the actual current draw before assigning any device to a PDM output.
• Use external relays when load demand exceeds the PDM channel capacity.
• Keep all shared-fuse loads within their allowed combined current.
• Use sound grounding practices throughout the system.

13. Startup and Verification

After all wiring is complete:

1. Verify all connections against the final wiring plan.
2. Confirm proper fuse placement.
3. Reconnect battery power.
4. Turn the ignition key to ON and verify correct system activation.
5. Confirm ECU power-up.
6. Test fuel pump operation.
7. Test fan activation through the EFI control strategy.
8. Verify communication between the ECU and connected peripherals.
9. Confirm tachometer response if the POINT circuit is used.
10. Start the engine and verify normal operation of all connected systems.

Inspect the wiring during initial startup for heat, loose terminals, abnormal voltage drop, or unintended switching behavior.

14. Troubleshooting

Issue	Checks
No Power to Module	Check VBAT and GND first. Inspect the main fuses for continuity. Verify battery voltage at the input and confirm the ground path is solid.
Fuel Pump Not Operating	Verify RPUMP control input. Check for voltage at VPUMP when the pump is commanded on. Inspect fuse F2 and verify fuel pump current draw is within range.
Fan Not Operating	Verify the correct control input is being used. Check for voltage at VRLY1, VRLY2, or VFAN as applicable. Confirm whether the fan is meant to be powered directly or triggered through an external relay. Verify total current remains within the channel and shared-fuse limit.
Ignition-Switched Outputs Not Active	Verify IGNKEY receives the correct keyed voltage. Confirm the source remains active during cranking. Check IGNSW1, IGNSW2, and IGNSW3 for proper output when IGNKEY is active.
Tachometer Issues	Confirm correct wiring to the POINT circuit. Verify the signal source and tachometer ground. Treat POINT as a signal circuit only.
Unpredictable Operation on Gen 1 or Hybrid Systems	Inspect for duplicate switching paths. A circuit may still be controlled by the original relay system while also receiving power from a PDM output.

15. Maintenance

Periodically inspect all electrical connections for:

• Corrosion
• Looseness
• heat damage
• Abrasion
• damaged insulation

Replace fuses only with the correct specified values.

Recheck grounds and high-current connections as part of routine service.

16. Safety and Operating Limits

Observe the following precautions at all times:

• Do not reverse the positive and negative power input connections.
• Do not exceed the rated current of any output channel.
• Do not exceed the total current limit of channels sharing the same fuse.
• Do not hot-plug the power supply while the load is operating.
• Do not expose the module to input voltage above 22 V.
• Remember that short-circuit protection is provided by the fuses. The module does not include active overcurrent protection.

17. Support

For technical assistance, contact Aces EFI customer support.

When requesting support, be prepared to provide:

• system type
• Gen 1 or Gen 2 configuration
• wiring layout
• connected loads
• measured current draw where applicable
• any relay integration details relevant to the installation