Dakota Digital VHX-78C-MC User Manual (English)

Questions and Answers:

M
Marc NunezAug 19, 2025
What to do if Dakota Digital Measuring Instruments speedometer will not show a reading?
- A
  Andrew GarrisonAug 19, 2025
  If the speedometer on your Dakota Digital Measuring Instruments isn't showing a reading, it could be due to connection issues or compatibility problems. Begin by verifying that all speed sending unit wires are correctly connected to the control box. Ensure you are using the speed sending unit supplied with the display system. Also, check that the sending unit is properly mounted to the transmission and that the transmission has the correct internal parts. Finally, make sure the sending unit wire is isolated from motor and ignition wires to prevent noise interference.
B
Bradley BlankenshipAug 21, 2025
Why is my Dakota Digital Measuring Instruments tachometer not showing a reading?
- M
  Matthew WolfAug 22, 2025
  If your Dakota Digital Measuring Instruments tachometer isn't displaying a reading, it could be due to several reasons related to connections or settings. First, ensure the control box is properly connected to your specific ignition system. Check the connections at both ends of the tachometer signal wire to make sure it is not loose or broken. If the connections are good, verify that the engine cylinder setting is correct by referring to the tach setup section of the installation manual. Also, confirm that the tach signal setting is correct by referring to the tach setup section of the installation manual.
K
Kristen LeeAug 25, 2025
Why is Dakota Digital VHX-78C-MC speedometer reading too fast?
- J
  Joseph LewisAug 25, 2025
  If your Dakota Digital Measuring Instruments speedometer is reading too fast or too slow, the speedometer is not calibrated. Refer to the 'Speed Calibration' section of the installation manual.
K
Kyle AbbottAug 26, 2025
What does 'EE' mean on Dakota Digital VHX-78C-MC Measuring Instruments display?
- B
  Brittney PetersonAug 27, 2025
  If a display on your Dakota Digital Measuring Instruments shows 'EE', it indicates a problem with the sending unit connection or type. Check the wire from the sending unit to the control box for breaks. Ensure the sending unit is properly grounded at the control box. If it's the water or oil gauge, use the water and oil senders that were supplied with the system. For the fuel gauge, refer to 'Fuel Setup' section of the installation manual to ensure that the settings match your fuel sender.
C
Chris BrightAug 28, 2025
Why Dakota Digital Measuring Instruments speedometer reads higher than zero when vehicle is still?
- C
  chadwoodwardAug 28, 2025
  If your Dakota Digital Measuring Instruments speedometer reads higher than zero while the vehicle is stationary with the engine running, it may be due to interference or grounding issues. Try rerouting or isolating the tachometer wire away from the speed wire. Also, ensure that the ground wire for the speed sensor is connected directly to the control box ground.
J
jmurphyAug 30, 2025
How to fix incorrect oil or water reading on Dakota Digital Measuring Instruments?
- P
  Paula RamosAug 30, 2025
  If the oil or water reading on your Dakota Digital Measuring Instruments is incorrect, make sure wires are in correct terminals. Check if the sending unit wire is picking up noise from nearby wires and isolate the sending unit wire from motor and ignition wires. Also, use the sending unit provided with the display system.
B
Beverly ShawSep 1, 2025
What does '--' mean on Dakota Digital VHX-78C-MC Measuring Instruments display?
- K
  Kevin BaileySep 1, 2025
  If a display on your Dakota Digital Measuring Instruments shows '- -', it suggests a problem with the sending unit wire. This could mean the sending unit wire for that gauge is shorted to ground; repair or replace the shorted wire. Also, check the wire from the sending unit to the control box for breaks.
M
Michael DyerSep 3, 2025
What to do if Dakota Digital Measuring Instruments system does not turn on and LED is flashing?
- A
  Alexandra BakerSep 3, 2025
  If your Dakota Digital Measuring Instruments system isn't turning on and the LED is flashing, the display system may not be getting power. Check the patch cable between the display system and control box. Also, check the display system wiring harness for broken or cut wires.
R
Robin RobinsonSep 6, 2025
How to correct an incorrect tachometer reading on Dakota Digital Measuring Instruments?
- P
  parkerstricklandSep 6, 2025
  If the tachometer reading on your Dakota Digital Measuring Instruments is incorrect, check the connections at both ends of the tachometer signal wire. Also, refer to the 'Tach Setup' section of the installation manual to verify the engine cylinder setting.
W
William PerezSep 8, 2025
Why Dakota Digital Measuring Instruments fuel displays '?' and gauge stays at empty?
- C
  Christopher MooreSep 8, 2025
  If the fuel display on your Dakota Digital Measuring Instruments shows a '?' and the gauge remains empty, the control box is set to an invalid fuel sender setting. Refer to 'Fuel Setup' section of the installation manual to ensure that the settings match your fuel sender.

Dakota Digital VHX-78C-MC Specifications

General

Brand	Dakota Digital
Product Name	VHX-78C-MC
Category	Measuring Instruments
Series	VHX
Display Type	Digital
Voltage	12V
Fuel Level Sensor Type	Ohm
Operating Temperature	-40°F to 185°F

Summary

VHX-78C-MC Installation and Components

VHX-78C-MC Kit Contents

Lists all items included in the VHX-78C-MC kit.

Step 1: Bezel Removal

Instructions to remove bezel screws for installation.

Gauge Removal Steps

Steps 2 & 3: Removing Factory Gauges

Instructions for removing the blackout plate, lens, and factory gauges.

Housing Preparation and Display Mounting

Steps 4-6: Housing Modification and Display Mounting

Details on preparing the housing and mounting the new display.

Final Installation Assembly

Steps 7 & 8: Final Assembly

Completing the physical installation and reattaching the bezel.

VHX System Introduction

Important Odometer Preset Note

Reminder about the odometer preset option timing.

VHX Instrument System Features

Display Capabilities and Indicators

Overview of LCD displays, mileage, performance, indicators, and special outputs.

System Handling and Mounting

Care and Cleaning Guidelines

Guidelines for cleaning the VHX system components.

Control Box Mounting Instructions

Instructions and considerations for mounting the control box.

VHX System Wiring

Wiring Diagram Overview

Explains the wiring connections for the VHX system.

Control Box Terminal Descriptions

Status LED and Grounding

Explanation of the status LED and the importance of proper grounding.

Constant Power Connection

Details on connecting the constant power terminal.

Accessory Power and Tachometer Connections

Accessory Power (ACC. POWER)

Instructions for connecting the accessory power terminal.

Tachometer Signal Connection

Guidance on connecting the tachometer signal wire.

Speed Signal Connections

SPD + and SPD SND

Instructions for connecting the speed sensor positive and signal wires.

SPD -

Instructions for connecting the speed sensor ground wire.

Speed Output and Switch Inputs

Speed Output and Switch Terminals

Description of speed output and switch inputs (SW1, SW2).

Water and Oil Sensor Connections

Water Temperature Sensor (WTR SND)

Details on connecting the water temperature sender.

Oil Pressure Sensor (OIL SND)

Details on connecting the oil pressure sender.

Fuel Sensor and Auxiliary Connections

Fuel Level Sensor (FUEL SND)

Instructions for connecting the fuel level sender.

Auxiliary I/O and Display Cable

Notes on AUX I/O and display cable connections.

Indicator Input Connections

Cruise, Wait, Gear, 4x4, Turn Signals, High Beam

Describes connections for various indicator inputs.

Warning, Dimmer, and Other Connections

Brake, Check Engine, and Dim Connections

Instructions for connecting brake, check engine, and dimmer signals.

AUX I/O and Display Cable

Notes on AUX I/O and display cable connections.

Control Box Setup Menus Overview

Speed and Tachometer Setup

Overview of the SPEED and TACH setup options.

Volt, Water, Oil, and Fuel Setup

Overview of VOLT, WATER, OIL, and FUEL setup options.

Speedometer Setup and Calibration

Speed Sensor Setup

How to select the speed sensor input type.

Speedometer Calibration Methods

Auto Cal Procedure

Step-by-step guide for automatic speedometer calibration.

Adjust Mode Calibration

Method for calibrating the speedometer manually.

Speedometer Setup Options

Service Countdown and Speed Output

Setup for service reminders and speed signal output.

Tachometer Setup Options

Engine Cylinder and Update Rate

Configuring engine cylinders and display update rate.

RPM Warning and Signal Setup

Setting RPM warning points and tach signal type.

Volt and Water Temperature Setup

Volt Warning Setup

Configuring low voltage warnings.

Water Temp Sensor Setup

Selecting units and sensor type for water temperature.

Water Temperature Setup Options

Temp Warning and Test Modes

Setting temperature warnings and using the test mode.

Oil Pressure Setup

Oil Pressure Warning and Test

Configuring oil pressure warnings and using the test mode.

Fuel Sender Setup

Fuel Sender Type Selection

Choosing from pre-programmed or custom fuel sender types.

Fuel Sender Calibration and Testing

Custom Fuel Sender Curve Setup

Calibrating a custom fuel sender.

Fuel Sensor Test and Exit

Testing the fuel sensor and exiting setup.

Lighting Setup

Night and Day Brightness Adjustment

Setting backlight levels for different driving conditions.

Display and Indicator Configuration

Secondary Indicator Setup

Configuring indicator display locations.

Display Message Location

Selecting which LCD displays show readings.

Information and Odometer Setup

Information Menu (Software Version)

Accessing system information like software version.

Odometer Preset Menu

Setting the odometer to match the vehicle's current mileage.

LCD Message Contrast Adjustment

Normal Operation and Message Displays

Speed/LCD1 Message Displays

List of messages for the speedometer display.

Tach/LCD2 Message Displays

List of messages for the tachometer display.

Troubleshooting Guide: Power and Status

Power and LED Issues

Solutions for systems not turning on or LED status problems.

Troubleshooting: Speed and Tachometer Readings

Speedometer and Tachometer Issues

Solutions for incorrect or missing speed/tach readings.

Troubleshooting: Gauge and Indicator Functionality

Gauge and Indicator Problems

Solutions for fuel, oil, water, gear, and indicator problems.

VHX Series Specifications

Supply, Inputs, and Outputs

Technical specifications for power, inputs, and outputs.

Service and Warranty Information

Service and Repair Procedures

Guidelines for returning units for service or repair.

Dakota Digital Limited Lifetime Warranty

Details of the product warranty.

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Table of Contents