Geotab HRN-RC12T2 Harness

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What Is the HRN-RC12T2?

The HRN-RC12T2 is a 12-pin harness that connects a Geotab GO RUGGED to Komatsu equipment from 2010 onward, but only where the machine has a Tier 4 engine. Geotab is explicit that it does not function on Tier 3 engines. The harness is 42 cm (17 in) long.

That Tier 4 condition is the most important fact on this page. Komatsu fleets built around 2010 to the mid 2010s can include machines on either side of the emissions change, and two excavators of the same model may carry different engine tiers depending on build date and market. Geotab's GO9 RUGGED documentation places this harness in the construction, mining, forestry and industrial equipment space, which is exactly where mixed-age Komatsu fleets turn up.

Which Vehicles and Devices Does the HRN-RC12T2 Work With?

Geotab lists the harness for Komatsu vehicles from 2010 onward, used with the GO RUGGED device, and limits it to Tier 4 engines. Typical candidates are hydraulic excavators, wheel loaders, dozers and similar Komatsu machines working on construction, quarry and forestry sites. The harness is not listed as replacing an earlier part, and no separate base harness is named.

At 42 cm, the harness leaves plenty of the 2 m connected cable maximum available for positioning the device. In practice the cab fuse panel is close enough to most good mounting spots that the stock length is all that is needed.

What Problem Does It Solve on the Job?

Komatsu machines generate useful engine data, and an owner running a GO RUGGED fleet across several brands wants that data in one place rather than split between different portals. The RC12T2 gives the Geotab device a proper connection to the Komatsu data network, so the engine information the machine shares can sit alongside the rest of the equipment in MyGeotab.

It also avoids the shortcut that causes trouble on these machines. Without the correct harness, an installer might fall back on a three-wire power connection, which tracks location and an ignition-based hour count but nothing from the engine. On a Tier 4 machine with aftertreatment systems to watch, losing the engine data defeats much of the reason for installing telematics in the first place.

How Is the HRN-RC12T2 Installed?

Geotab publishes a Komatsu Tier 4 installation document for this part. The steps below summarise that procedure together with the general GO RUGGED requirements:

1. Confirm the engine is Tier 4 from the engine data plate, and record the device serial, machine serial and hour meter. Register the device serial before starting.
2. Shut the machine down and leave the GO RUGGED unplugged until the harness is in place.
3. In the operator's cab, find the OEM data connector, usually at the fuse panel, and unclip it from its bracket. Clip the harness's C3 connector into that bracket.
4. If the OEM connector had a data connector or terminating resistor attached, move it onto C3.
5. Plug C2 into the OEM data connector, then connect C1 to the GO RUGGED.
6. Mount the device where the harness reaches comfortably and where cellular and GPS reception are good. Tie down the device and both sides of each joint, keep the full run within 2 m (6.5 ft), and never chain T-harnesses.
7. Start the machine and allow up to five minutes for initialisation, during which the device beeps. Check that the red ignition, blue GPS and green cellular LEDs are lit, then confirm Pass in MyInstall.

Which Related Harnesses Should You Compare?

• HRN-DC14T1: the 14-pin T-harness for CAT machines from 2016 onward.
• HRN-RL12K2: a 12-pin kit for off-road machines with Deutz engines.
• HRN-RW07T1: the tri-pin CAN harness for machines that have no diagnostic port at all.
• HRN-RW03K4-A: a rugged three-wire power kit, useful on a Tier 3 machine where this harness will not work.

What Are Common Questions About the HRN-RC12T2?

Will the HRN-RC12T2 work on a Komatsu with a Tier 3 engine?

No. Geotab states the harness only functions on Tier 4 engines, even though it is listed for Komatsu vehicles from 2010 onward.

Where is the Komatsu data connector usually found?

Geotab's instructions place the OEM data connector in the operator's cab, typically in the fuse panel area.

What happens to a terminating resistor already on the OEM connector?

If the OEM connector carries a data connector or terminating resistor, Geotab's procedure moves it onto the harness's C3 connector so it stays in the circuit.

Komatsu machines on your site can be fitted where they stand: API Signal supplies the Geotab device and harness and handles the installation in the cab. Ring 803-513-1009 or open Get a Quote to set a date.

Sources: Geotab harness identification, Geotab Komatsu Tier 4 installation, HRN-RC12T2, Geotab GO9 RUGGED. GEOTAB is a registered trademark of Geotab Inc. API Signal is an independent installer and is not Geotab.