The Digital Age: Updating Your Gauges For An LS Swap

Gauges are an essential part of any vehicle. They relay an engine’s vital signs back to the operator, letting them know if everything is good or not. And over the years, with the introduction of electronic fuel injection (EFI), as the automobile became more advanced, so did the electronics and motoring system. But, when it comes to LS swaps, the gauges are often overlooked at first. Sure, after the vehicle is running and driving, then gauges become pretty obvious. But hooking them up to an LS swap can be a real pain, whether the car is new or old. 

Depending on the vehicle, sometimes you will need to run extra sensors for coolant or drill and tap for an added oil port to get a factory set of gauges to work. But, when it comes to adapting over a factory tach or mechanical speedometer, things can get even more involved and complicated. And while the automotive aftermarket offers parts and products to make old gauges work with a modern drivetrain, Dakota Digital provides something even better with its instrument clusters and expansion modules.  

The factory gauges in our Squarebody have seen better days. And instead of trying to fix them, it was easier to replace the instrument panel with Dakota Digital’s RTX Series gauges.

In 1996, vehicle manufacturers started incorporating a plug known as an OBD II or the second-generation On-Board Diagnostics system. As most of you know, this plug allows mechanics to tap into the vehicle’s engine control unit (ECU) and check the codes when the check engine light is on. This same port is also used for tuners when an engine is modified. If this port allows technicians and tuners to pull data in real-time, why couldn’t Dakota Digital do the same thing and use it for the instrument cluster? Well, it turns out they could. 

We reached out to Scott Johnson, Marketing Director at Dakota Digital to get more information about this new wave connection. Johnson said, “With OBD II standards, this connection point allows for easy access to data which already exists and can be shared with other devices. In addition, it provides a much quicker gauge installation, far less wiring, less plumbing, and a gauge display consistent with the OEM computer readings.”

Dakota Digital’s RTX instrument panel

We ordered Dakota Digital’s RTX instrument panel (PNRTX-79C-PU-X) and the OBD-II / CAN interface module for our installation. The RTX series is a modern cluster that pays tribute to some of the gauges of yesteryear. This unit lays out in the stock bezel with dedicated gauges for voltage, oil pressure, fuel level, temperature, speedometer, and tachometer, which is already an upgrade since the factory unit didn’t have a factory tach. But the RTX gauge set brings even more to the table with the addition of two thin-film-transistor (TFT) screens, which are a variant of a liquid-crystal display that uses thin-film-transistor technology. 

Here’s a good look at everything that comes with the RTX gauge set with the addition of the BIM module and OBD II cable.

“The TFT screen found in the RTX Series is similar to many late-model vehicles, providing you with a programmable message or display screen,” explained Johnson. “Using our system’s push-button navigation, the user can cycle through various readings, diagnostics, as well as crisp lighting and color options, all of which are an easily readable day or night.”

RTX Installation

The installation process for the new gauge set is straightforward on a Square-body and most vehicles. First, we removed the instrument bezel, which would allow us access to the factory instruments. Then we removed the four screws that hold the gauges in place. After we unplugged the harness and a couple of lights, the cluster can be pulled out and set aside. At this point, we were ready to install the new Dakota Digital RTX Instrument system. Dakota Digital sends a 36-page instruction booklet with the gauges, and we highly recommend reading it before you start the installation.

With over 30 years of service, the factory gauges looked the part. The lens was cloudy, and the temperature gauge was broken as well as the gear indicator.

We started with the gauge control box and mounted it behind the gauge cluster. After the control box mounting location was established, it was time to dive into the wiring. First, we jumped online to find a schematic for our particular vehicle to determine what wires we needed to run to the control unit with the box installed. This cut down on a lot of guesswork and wire probing, allowing us to put each wire in its prospective place. From there, we plugged the corresponding wires into the slots on the control box. Everything is labeled, and the instructions are very detailed if any questions arise. 

We mounted the gauge control box to the firewall and then removed it to start the wiring process.

With all of the accessible wires from the factory gauge cluster tied into the control box, we plugged in Dakota Digital’s BIM-01-2 OBD-II / CAN interface module (PN J1850/CAN). With the BIM module, you don’t need to run extra sensors like water temperature, tach signal, or oil pressure since it deciphers all of the data from the OBD-II port off our LS harness. It also pulls all of the information for the speedometer, alleviating any headaches caused by sticking an electronic transmission in an older vehicle.

The BIM module uses the data steam straight from the OBD II port and transmits it straight to the instrument panel. It will automatically display information like engine temperatures, speed, boost, and oil pressure, just to name a few. These units can also be daisy chained for even more additions.

The BIM module can save hours of installation time, which can quickly pay for itself when considering the billable rate of most professional shops. In addition, the module allows us to pull data from the OBD-II port and convey information to the gauges and TFT screens that would typically not be accessible with standard gauges. Parameters such as intake air temperature, transmission temperature, gear position, and even boost pressure are now just a push of a button away. 

The majority of the wires we needed to operate our new gauges were removed from the factory gauge connector.

During the installation, we did find one problem: our standalone harness did not come standard with an oil pressure sensor plug, and from what we could find, most don’t unless the customer requests it. But, all we had to do was run the supplied Dakota Digital sensor in the back of the engine and run the wires to the control box. The only wires left to run for the gauge set were the fuel level sending unit. We were able to use the signal wire from the cluster harness. However, Dakota Digital recommends running a new ground wire back to the fuel tank and grounding it to the sending unit. And while this is somewhat of a pain, this step will ensure that we don’t have any interference from the electric fuel pump. 

With all of the wires routed and cleaned up, it was time to finish the installation and put the dash back together. After mounting the warning buzzer, we plugged it into the back of the cluster. We also routed the cable from the box to the gauges, which makes wiring simple. We then plugged in the OBD-II connector and attached the other end to the BIM module we previously connected to the control box. Next, we installed the toggle switch that will allow us to program the gauges and toggle through different displays of engine vitals. Finally, we set the new cluster in its position, but we didn’t button everything up just yet. Instead, we decided to program the gauges and ensure everything was functional before putting the interior pieces back together. 

With everything mounted and wired, it was time to put the dash back together.

There’s An App For That

Programming the gauges can be accomplished in one of two ways. The first method for programming is done by using the ‘I/O’ toggle switch. We held down the toggle per the instructions with the ignition off and put the key to the “ON” location. This action puts the gauges in setup mode. From there, you will scroll through the menu displayed on the TFT screen and set the parameters. The second method, which we prefer, required us to download an app for our mobile device, turning it into a tuning tool for the cluster. This route makes changing the gauge settings a snap, and it’s much quicker than the first method. 

Here is a look at just a few of the adjustments available through the Dakota Digita app. It’s very user-friendly and makes setting up the gauges a snap.

After we downloaded the app, we connected to our Dakota Digital instrument panel via Bluetooth without any problems. From there, we set the gauges up according to the instructions. Since we were using the BIM module, we needed to switch some of the data over so that the panel would receive information from the BIM module. Things like speed, RPM, coolant temperature, and transmission gear position are just a few examples. From there, we set up the fuel sending unit and the clock before moving on to the gauge illumination. 

Light ’em Up

If there’s one area we spent too much time on, it was setting a theme for our gauges, and we blame Dakota Digital entirely. You see, they give you a lot of options, and with the app, it’s easy to mix and match with an unlimited number of possibilities. We were able to change the brightness, colors of the pointers, color on numbers, daytime and nighttime settings, TFT screen displays, data, and a lot of other stuff. And while we finally figured out what we liked, which is a factory preset, we know that it will change in the future. 

With the app, you can adjust the colors of the gauges. Here is a look at some of the preset colors you can choose from. However, if you want to customize the colors, even more, you can do that as well. The choices are almost endless.

At a glance, you can tell these gauges are a massive improvement over our worn-out units based on looks alone. But there’s much more to the Dakota Digital product than meets the eye. 

“Like the numerous benefits of an LS swap over whatever came under the hood from the factory, we can see many parallels to the RTX Series replacing stock gauges,” Johnson explained. “From modern solid-state electronic components to LED lighting for unparalleled visibility to the ease of interface with today’s vehicle computers, the RTX series is uniquely a ground-up design just for the needs of the performance automotive aftermarket. Couple this with the period-correct look of the OEM gauges, and we have genuinely defined the popular term of Restomod.”

The RTX gauges may look factory when they are powered off. However, they indeed come to life after the ignition is switched on.

And while these gauges may look like factory units with the key off, it’s a whole new world when the ignition is turned on. They offer outstanding visibility in the daytime and at night, making it easy to keep tabs on your engine’s vitals. But if there is a problem with oil pressure, voltage, or water temperature, the cluster can be programmed to send you a warning through the buzzer, letting you know something has gone array. 

The TFT screens are fantastic as they display more information than you could have with a standard set of gauges. Here you can see the gear position, odometer, speed, clock, and trip meter.

More To Come

While some might consider the Dakota Digital gauge set near perfect, the company continuously improves them and how the instruments receive information. Johnson said, “The communication process through the OBD II port is a living project for our in-house engineering team, always under the state of potential updates and improvements. As new OEM and aftermarket drivetrains become available, our engineering team takes time to search for new OBDII data that may be available. This allows additional features or readouts in some cases or may cast a wider compatibility net. We all love the idea of ‘Plug and Play,’ and while this isn’t always practical in the automotive aftermarket, this is one giant step toward that ideal.” 

The app also allows the user to see the gauges in real-time straight from a mobile device.

That’s A Wrap

After driving the Suburban around with the new RTX instruments, we can tell you it’s well worth the investment and one we wished we had done sooner. Unfortunately, our factory gauges were not in the best shape. The gear indicator was broken, the oil pressure gauge didn’t read correctly, half the lights were burnt out, the temp gauge never worked, and we didn’t have a factory tach. The Dakota Digital gauges eliminated all of these problems in one fell swoop. The instruments are easy to read and navigate, and with the BIM module, we can access even more information in real-time and see exactly what’s going on with the engine, which certainly adds to our peace of mind especially on long road trips.

You can customize the colors of the gauges, the TFT display, and even the pointers to match the theme of your vehicle.

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About the author

Brian Havins

A gearhead for life, Brian is obsessed with all things fast. Banging gears, turning wrenches, and praying while spraying are just a few of his favorite things.
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