Mastering Geotab
★ Geotab Harnesses · Make-Specific and Custom Harnesses
The HRN-AX04S1 is a Geotab adapter harness that plugs an IOX-AUXM into the existing Zonar connector on a school bus, so the GO device can record signals such as overhead lights, door open and lift door without rewiring the bus.
The HRN-AX04S1 is a Geotab adapter harness for school buses already fitted with Zonar equipment: it joins an IOX-AUXM module to the bus's Zonar connector so the GO device can log auxiliary signals like the overhead warning lights, door open and the lift door. Rather than tracing and tapping each circuit again, our technicians plug into wiring the bus already has.
Districts and contractors that move their buses onto Geotab usually inherit years of earlier wiring work. This harness turns that work into an asset instead of something to rip out.
Geotab lists this adapter for school buses with existing Zonar equipment. It connects the IOX-AUXM to the bus's Zonar connector, and the signals named are overhead lights, door open and lift door. The listing gives a length of 75 cm (29.5 in) and China as the origin; it names no replaced part.
The IOX-AUXM is the module doing the reading. Geotab describes it as an expansion that connects to the GO device and uses the GO's CAN link, with up to four digital inputs per unit and room to chain a second unit later. It handles ground-to-float, ground-to-driven and float-to-driven signals and learns the input signal on its own. So the full stack on the bus is the GO device, the IOX-AUXM, and this adapter running to the Zonar connector.
When a bus fleet changes telematics systems, the expensive part is rarely the tracker. It is the hours spent finding the red light circuit, the stop arm, the door and the lift on every bus, then tapping each one. If those signals were already brought to a Zonar connector, the HRN-AX04S1 lets the new system pick them up from the same place.
The data itself matters for safety and records. Knowing when the overhead lights came on and when the door opened, tied to GPS location, helps a transportation office answer parent and incident questions with facts rather than memory. Lift door events add a timestamped record each time that door was opened on a route.
We plan each bus as its own job, since equipment placement differs between body builders. A typical flow:
Whatever harnesses the bus needs for the GO device itself, the combined length stays within Geotab's 2 m (6.5 ft) limit, and T-harnesses are never stacked.
| Spec | Detail |
|---|---|
| Part number | HRN-AX04S1 |
| Country of manufacture | China |
| Vehicle | School buses with existing Zonar equipment |
| Connects | IOX-AUXM to the bus's Zonar connector |
| Signals named | Overhead lights, door open, lift door |
| Length | 75 cm (29.5 in) |
| IOX-AUXM inputs | Up to four digital inputs per unit; two units can be chained |
Do not assume every pin on an old Zonar connector is still wired; buses get repaired, rebodied and modified, so meter each signal before trusting it. Confirm which input the lights, door and lift land on so MyGeotab rules are named correctly. Keep the IOX-AUXM away from heater ducts and the door mechanism. If a bus has more signals than one IOX-AUXM can take, plan the second unit at the start rather than adding it on a later visit.
No. The point of the harness is to reuse the bus's existing Zonar connector, so the auxiliary signals already wired to it can feed the IOX-AUXM and the GO device.
Geotab describes the IOX-AUXM as having up to four digital inputs per unit, and two units can be chained when more inputs are needed.
Geotab lists the HRN-AX04S1 at 75 cm, about 29.5 inches.
Bus changeovers run smoother when the crew has seen plenty of old wiring, and our technicians bring 35 years of twelve-volt work to every one. API Signal supplies the Geotab harnesses, IOX modules and GO devices and installs them at the customer's yard or bus lot. Ask for a time on 803-513-1009, or use Get a Quote with your bus count.
Sources: Geotab harness identification, HRN-AX04S1; Geotab Marketplace, IOX-AUXM. GEOTAB is a registered trademark of Geotab Inc. API Signal is an independent installer and is not Geotab.
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