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DL1FDHowDoI / WiringExternalLEDsToTheDL1FDAUXConnector

How to Wire External LEDs to the DL1 FD AUX Connector

The DL1 FD’s AUX 9 way D type male connector provides several LED outputs:

• Logging LED
• Status LED
• GPS Lock LED
• Power LED

These outputs are open collector / open drain to ground. That means:

• The DL1 FD does NOT supply power to the LEDs
• The DL1 FD does NOT include current limiting resistors
• Each LED output simply pulls to ground when active

So you must provide:

1. An external +V supply (typically 5–12V)
2. A series resistor for each LED
3. The LED itself
4. Return the LED negative to the DL1 FD AUX pin

🔧 Correct Wiring Method

Here’s the safe, recommended wiring:

1. Choose your supply voltage

• 5V or 12V both work
• Use a resistor sized for your supply

2. Wire each LED like this

3. When the DL1 FD activates the LED

• The AUX pin pulls to ground
• Current flows through the resistor → LED → DL1 FD pin
• LED lights up

4. When the DL1 FD deactivates the LED

• The AUX pin is open circuit
• No current flows
• LED turns off

Typical Resistor Values

For a standard 20mA LED:

If you want the LEDs dimmer (recommended for dashboards), use:

• 330 Ω on 5V
• 1 kΩ on 12V

DL1 FD AUX Connector Pinout (relevant pins)

Important: Pins 6 and 8 are 5V reference outputs — you can use them to power LEDs, but don’t overload them. If you want multiple LEDs, it’s safer to use an external 5–12V supply.

⚠️ Important Safety Notes

• Do NOT connect LEDs directly to the DL1 FD pins — you will damage the output transistor.
• Do NOT exceed 20mA per LED output — keep current low.
• Do NOT tie the LED cathode to chassis ground — it must return to the DL1 FD AUX pin.
• If using 12V, always use a resistor ≥ 470 Ω.