Hub Screw Terminal Overview

Analog Inputs (A1-A6): Temperature, Fuel Level, and Pressure

• These inputs are used for analog sensor inputs.
• A1, A2, and A3 are programmed specifically to work with Autometer 2258/2259 temperature sensors. A1 is coolant temperature, A2 is oil temperature, and A3 provides transmission temperature readings.
• These are one-wire sensors that ground through the threads, so please ensure that no thread tape is used when installing the sensor.
• Screw terminal A4 is used as the fuel level input.
  • To read your vehicle’s fuel level, your vehicle should have an in-take sender or float that changes resistance as fuel level changes. These senders typically have two wires. One should be grounded, and the other attached to the assigned Fuel Level terminal. Please ensure that the vehicle is not also sending voltage through any of these wires. The Fuel sender should be connected only to the OneGauge and not to the vehicle except to ground.
  • The OneGauge hub can be calibrated to any fuel sender’s resistance range. If you purchased a Standard LCD touchscreen from OneGauge you can program the resistance yourself through the setup menu (touch in the top left corner of the screen). Otherwise, please provide the resistance of the sender at full and empty when you purchase your unit so it can be programmed appropriately, or contact OneGauge to receive a code update with the correct resistances pre-programmed.
• Screw terminal A5 is used a second fuel level input and the instructions are the same as above.
• Screw terminal A6 is used as an analog oil pressure input (Standard Motor Products PS60T). OneGauge typically does not recommend these sensors, so by default digital oil pressure sensors are recommended and used as the Oil Pressure reading on standard OneGauge screens.

Digital Inputs (B1-B7): Pressure and Air/Fuel Ratio

• These inputs are designed for 0-5v pressure sensor signals or Air/Fuel ratio signals.
• Port B1 is designed for use with a 3-Bar, GM Style MAP sensor that provides pressure readings up to 30 PSI as well as vacuum readings.
• Ports B2, B3, and B4 are programmed for use with 100 PSI digital pressure sensors. Port B2 is designated Fuel Pressure, B3 Oil Pressure, and B4 Additional Pressure 1.
• Port B5 is programmed for use with a 200 PSI digital sensor and is designed Additional Pressure 2.
• Ports B6 and B7 provide AFR and AFR2 readings, respectively. These are programmed to work with the output of a Spartan Oxygen Sensor by default, but we support any AFR controller with a 0-5v analog output. Please see installation notes in the “Sensor and Sensor Installation section” below for critical information about powering your Oxygen Sensor and Controller.
• These ports can be configured by request for a huge variety of pressure sensors, so please inform us when ordering if this is required.
• Digital sensors typically require 5v power; numerous 5v power and Ground (-) screw terminals are provided on the Hub to power these sensors.

Voltage Inputs (C1-C2)

• Battery voltage is measured automatically by the OneGauge hub from the main power connection. The voltage reading on screen provides this reading.
• Additional voltage inputs are provided by C1 and C2 if required. These are designed to measure up to 25 volts.

Digital Temperature Sensors (D1-D4)

• These terminals are set up to read DS18B20 sensors, a commonly available and very accurate digital sensor. This type of sensor is typically available in probe-style, unthreaded varieties, but we offer threaded options as well.
• D1 is ambient air temp, D2 intake temp, D3 vent or cab temp, and D4 a digital coolant temp or additional temp option.
• Like digital pressure sensors, these require 5v power and Ground (-), so the terminals on the Hub can be used for this purpose.

Serial RX/TX Ports

• Not typically used –  instructions will be provided by OneGauge if these are to be used.

RPM Terminals

• These two screw terminals offer tachometer, speedometer, or other rotational speed measurement inputs.
• RPM1 is the primary tachometer input screw terminal. Use this for a standard tachometer reading.
• RPM2 provides an input for a pulse-based electronic speedometer or an additional driveshaft or other speed reading. Please reach out to OneGauge to ensure the unit is programmed according to your needs.
• Tachometer installation is detailed in Appendix C. It is the customer’s responsibility to find a tachometer solution that is appropriate for their vehicle.
• These two terminals are voltage protected and typically require 7+ volts to trigger a signal. OneGauge offers a variety of tachometer options to work with any engine, so please see the Tachometer Instructions for more information.

Indicator Terminals (I1-I5)

• These terminals provide inputs for 12-15v signals that can illuminate on screen indicators.
• I1, I2, and I3 are used as 12v indicator inputs. You can customize what light comes on when each is triggered by using the setup menu on the OneGauge LCD screen (see Appendix D and the Indicator setup screen for instructions).
• I4 is set as the left turn signal indicator and I5 as the right turn signal indicator.
  • Some vehicles have lower voltage turn signals that may delay triggering the turn signals on the screen if voltage is too low. In this case, you can move the left turn signal wire to terminal C1 and the right turn signal wire to terminal C2. Use the Other Settings menu (see Appendix D for instructions) to change “Turn Signal In” from 0 to 1 and your turn signals should be more responsive.