Mastering Geotab
★ Geotab Harnesses · Heavy-Duty Deutsch Harnesses
The HRN-CS14T2 is a 60 cm (24 in) Geotab T-harness that connects a GO device to a heavy truck's 14-pin RP1226 diagnostic connection. Geotab lists it for GO9 and, with the HRN-XBS16A1 bridge, for GO10.
The HRN-CS14T2 is a 14-pin heavy-duty T-harness for vehicles that offer an RP1226 diagnostic connection. It measures 60 cm (24 in) and gives the GO device its own branch while the RP1226 connection continues through the T.
Geotab's cheat sheet frames the 14-pin RP1226 connection as an alternative to the familiar 9-pin port on some trucks from 2019 onward. On those trucks, a fleet has a choice of where to connect, and this harness makes the 14-pin route practical. Among the 14-pin options, the HRN-CS14T2 stands out for one reason: it is the part Geotab lists for both GO9 and, with an added bridge, GO10. That makes it the natural pick for fleets in the middle of a hardware changeover.
Geotab's cheat sheet names some 2019 and newer heavy trucks as carriers of the RP1226 connection, giving Freightliner, Mack, Volvo, Peterbilt and Western Star as examples. Not every truck of those makes and years will have it, so we check the actual cab before choosing between this harness and a 9-pin kit.
For GO9, the HRN-CS14T2 connects directly. For GO10, Geotab lists it together with the HRN-XBS16A1, a short bridge adapter that lets a GO10 use specialty harnesses that have no GO10 version. One compliance point applies: with a GO10 in California, Geotab allows that bridge only on a direct connection to the vehicle's data link connector or on a harness that is not in a T configuration, which rules out this T-harness pairing there.
Geotab's notes add a firmware condition: the harness works only with devices running firmware X.23.XX or newer. Current devices will normally meet that, but a unit pulled from storage might not.
On a newer tractor, the RP1226 connection gives telematics a dedicated place to land, which keeps the 9-pin diagnostic port for the shop. The T design goes a step further by passing the 14-pin connection through, so anything else the truck uses on that connection is not shut out by the GO device.
For fleets moving from GO9 to GO10, it also simplifies parts. The same harness serves both device generations on these trucks, with only the bridge added on the GO10 side outside the California restriction, so a mixed yard does not need two different 14-pin harnesses on the shelf.
The one surprise installers meet is power. Geotab built the harness to draw power from pin 14, but some vehicles supply it on pin 1. Knowing that before the job saves a confusing first power-up.
With the truck parked and the ignition off, locate the RP1226 connection, connect the harness's 14-pin end, and reconnect the truck side to the pass-through. Route the GO device branch to a secure spot, connect the device (with the HRN-XBS16A1 between them on a GO10), and cable-tie the device and harness so nothing hangs near the pedals.
Geotab's vehicle notes then give a short power check. Power the truck and see whether the device switches on. If it does, the connection is done. If it does not, find out which pin carries power. When power is on pin 1, move the harness pin from position 14 to position 1. When power is on pin 14 and the device still stays dark, our technicians work through it with Geotab rather than leaving the truck unfinished. If neither pin works, or a different power source is preferred, Geotab's notes allow the exposed wire on the battery connector to be joined to an active power source, done with the vehicle off.
Keep the total connected harness length within 2 m (6.5 ft), and never join this T-harness to another T-harness. Once powered, let the device initialize, then complete the MyInstall check and confirm the truck reports in MyGeotab.
| Spec | Detail |
|---|---|
| Part number | HRN-CS14T2 |
| Type | 14-pin heavy-duty T-harness |
| Vehicle connection | RP1226 diagnostic connection |
| Length | 60 cm (24 in) |
| Device | GO9 directly; GO10 with HRN-XBS16A1 |
| Firmware | X.23.XX or newer |
| Power pin | Pin 14 by design; some vehicles use pin 1 |
| California note | HRN-XBS16A1 with GO10 not permitted in a T configuration |
| Max connected cable length | 2 m (6.5 ft) |
| Country of origin | China |
Meter the power pins before blaming the device, because a dark GO unit on an RP1226 truck may simply be a pin 1 versus pin 14 mismatch. Move the terminal with a proper extraction tool so the housing latch is not damaged. Check firmware on any stored device before installing. For GO10 trucks registered or primarily run in California, plan a different connection, since the bridge cannot be used with this T-harness there. Label the pass-through so the next technician knows what it is.
Yes, with the HRN-XBS16A1 bridge adapter between them, except in California, where Geotab does not allow that bridge in a T configuration.
The harness takes power from pin 14, but some vehicles supply it on pin 1. Geotab's notes say to move the pin from 14 to 1 in that case.
Yes. Geotab states it works only with devices on firmware X.23.XX or newer.
From newer tractors to mixed GO9 and GO10 yards, API Signal supplies the HRN-CS14T2, any bridge adapter needed and the devices, and installs them on site at your yard, where the trucks park. Get started at 803-513-1009 or through Get a Quote.
Sources: Geotab Harness Identification and Application, Geotab HRN-CS14T2 installation instructions, Geotab vehicle-specific installation notes, Geotab harness cheat sheet. GEOTAB is a registered trademark of Geotab Inc. API Signal is an independent installer and is not Geotab.
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