Geotab HRN-RZ04T41 Harness: Fitment, Install and Specs

What Is the HRN-RZ04T41?

The HRN-RZ04T41 is a T-harness that connects a Geotab GO RUGGED to the Ford EDI tug engine interface, built around the Ford MSG-425 2.5 liter engine. Geotab lists it as required for ground service equipment, and it supersedes the older HRN-RZ04S4. Its length is 110 cm (43 in).

Ramp tow tractors are a specialised corner of the fleet world. They move baggage carts and other loads around the apron, they work in short bursts across long shifts, and many of them use industrial versions of automotive engines rather than anything with a modern diagnostic port. The Ford MSG-425 is one of those engines, and this harness is Geotab's dedicated route into it. If a ramp fleet runs Ford-powered tugs, this is the part number that belongs on the work order.

As a T-harness it sits in line between two halves of the engine connection, with a branch that leads to the GO RUGGED.

Which Vehicles and Devices Does the HRN-RZ04T41 Work With?

Geotab lists the harness for the Ford EDI tug engine interface, with the Ford MSG-425 2.5 liter as the engine, and pairs it with the GO RUGGED device. It belongs to the small group of harnesses that Geotab's GO9 RUGGED documentation names for ground service equipment, which also includes the Kubota engine harness, the differential harness and the pulse harness.

The key replacement detail is that the RZ04T41 takes over from the HRN-RZ04S4. Fleets that have used Geotab on their tugs for a while may still have the older part number in their records, and new installs should use the T version. No separate base harness is listed. With 110 cm used by the harness, about 90 cm of the 2 m limit remains.

What Problem Does It Solve on the Job?

Tug utilisation is a constant question for ground handlers. Too few tugs and flights wait; too many and capital sits idle on the apron. Answering it needs accurate run time for every unit, and the MSG-425 does not hand that information over through a standard diagnostic connector. A generic power install can only guess at activity, which skews utilisation reports, idle tracking and service planning.

The engine-specific T-harness gives the GO RUGGED a defined connection to the Ford engine circuit, so the device knows when the tug is actually working. That supports decisions on fleet size, highlights units that idle excessively, and drives preventive maintenance from real hours. On a mixed ramp where some tugs run Kubota power, pairing each engine with its own Geotab harness keeps reports comparable.

How Is the HRN-RZ04T41 Installed?

Geotab's listing shows a documentation entry for this part but no linked file, so we work from the GO RUGGED installation guide and Geotab's harness rules:

Confirm the tug carries the Ford MSG-425 engine and note the device serial, unit number and hour meter. Add the serial to the database before the job.
Move the tug to a safe maintenance area clear of aircraft traffic, shut it down and keep the device unplugged.
If an older HRN-RZ04S4 is installed, remove it and restore the original engine connection first.
Fit the T-harness at the Ford EDI engine interface so the original connection carries through it, which is how a T-harness is designed to sit.
Run the device branch to a solid mounting point with a clear view of the sky, away from the exhaust and tow coupling.
Keep the total chain at or under 2 m (6.5 ft) and do not connect any second T-harness.
Tie down the device and every joint on both sides, start the engine, wait for the three LEDs to go solid, and confirm Pass in MyInstall.

The T-harness fits at the Ford engine interface, and its branch climbs to a device on the driver's frame, well clear of the hitch.

Spec	Detail
Part number	HRN-RZ04T41
Type	Ford EDI tug T-harness
Engine	Ford MSG-425, 2.5 liter
Replaces	HRN-RZ04S4
Equipment class	Required for ground service equipment
Compatible device	GO RUGGED (GO9 RUGGED)
Harness length	110 cm (43 in)
Maximum connected cable	2 m
Country of origin	China

What Should You Watch for When Fitting It?

Confirm the engine model on the tug itself, since older tugs may have been repowered with something other than the MSG-425. When swapping out an RZ04S4, return the original engine connection to factory condition before fitting the T version so no adapters are left stacked. Tugs sit low and pick up spray from wet aprons, so keep the device high and the harness above the frame rails. Leave a little slack where the body flexes, and check that the hitch area cannot catch the cable.

Which Related Harnesses Should You Compare?

HRN-RZ04T4: the Kubota gasoline and diesel engine harness for ground service equipment.
HRN-RW04K4: the differential harness for negative disconnects, oil pressure switches and negative ignition.
HRN-RW03K5: the pulse harness that reads the coil primary on engines with no ignition or RPM signal.

What Are Common Questions About the HRN-RZ04T41?

What part did the HRN-RZ04T41 replace?

Geotab lists the HRN-RZ04S4 as the part this T-harness replaces. When older ordering notes call for the RZ04S4, the RZ04T41 is the current part to supply.

Which engine is the HRN-RZ04T41 for?

Geotab names the Ford MSG-425, a 2.5 liter engine, used through the Ford EDI tug engine interface in ground service equipment.

Can another T-harness be added to the HRN-RZ04T41?

No. Geotab's harness rules forbid connecting two T-harnesses together, and the 110 cm length already uses more than half of the 2 m cable limit.

API Signal stocks and installs Geotab equipment for ramp fleets, fitting each tug where it is parked between shifts. Phone us on 803-513-1009 or describe your fleet on Get a Quote.

Sources: Geotab harness identification, Ford EDI tug entry, Geotab GO9 RUGGED harness list, Geotab harness length and T-harness rules, Geotab Installations GO9 RUGGED guide. GEOTAB is a registered trademark of Geotab Inc. API Signal is an independent installer and is not Geotab.

Every Geotab Harness →All 83 harnesses and accessories by part number. Get a Quote →The HRN-RZ04T41 supplied and installed on one written quote.

Geotab HRN-RZ04T41 Harness