Gomaco Stringline Grade & Steering Sensor - G+ / G21 Control System - Replaces 500-46D83 / 500-46D84 - Plug-and-Play Smart Sensor

Stringline Grade & Steering Sensor for Gomaco — Replaces 500-46D83

Keep your IRI numbers low and your paver moving. This is the OEM-specification smart sensor used on Gomaco G+ and G21 control systems — the "wand" that traces the yellow stringline and feeds grade and steering data to the paver's automated controls. Plug-and-play replacement for Gomaco 500-46D83 and 500-46D84. In stock at $985 — under $1,000, no purchase order delay.

The Problem

Your paver is "hunting" for grade — the machine oscillates left and right instead of tracking the stringline smoothly. Or worse, you've lost steering control entirely and the paver is wandering off the string. The G+ or G21 system is throwing sensor faults. Your concrete crew is standing around at $200+ per hour in combined labor, and the ready-mix trucks are circling the block with setting concrete in their drums.

You call the Gomaco dealer. They want $1,500–$1,800 for a replacement sensor, and it's on backorder for 5–10 business days. Meanwhile, you have 2,000 linear feet of concrete to pour this week and the DOT inspector is watching your IRI numbers.

The Solution

Same OEM-specification smart sensor used on Gomaco pavers from the factory. Designed for the high-vibration, high-dust, extreme-temperature environment of concrete paving. Plug-and-play — connects directly to your existing G+ or G21 wiring harness with no modifications. Replaces Gomaco 500-46D83 and 500-46D84.

Priced at $985 — deliberately under the $1,000 threshold so your superintendent can put it on a credit card and get the paver running today, without waiting for a corporate purchase order.

⚠️ Pro Tip: Keep a Spare in the Truck

If a sensor fails in the middle of a concrete pour, the concrete will set before the dealer arrives. A dead sensor during an active pour means you're finishing the slab by hand — or worse, ripping it out and starting over. At $985, this sensor is cheap insurance. Keep one in the service truck. When (not if) a wand fails mid-pour, you pull the spare out of the truck, plug it in, and you're pouring again in 10 minutes instead of losing the entire day.

Specifications

• Gomaco OEM Part Numbers: 500-46D83, 500-46D84
• Type: Smart Stringline Sensor (Grade & Steering)
• Control System: G+ and G21 Automated Control
• Function: Traces stringline for grade control and steering input
• Connector: 3-Pin Weatherpack (verify your specific plug type)
• Design: Sealed electronics, high-vibration rated, dust/moisture resistant
• Installation: Plug-and-play — direct replacement, no calibration required beyond standard G+/G21 setup
• Condition: Brand New

Identification

• Location: Mounted on the sensor arm (wand) — the arm that extends out and traces the yellow stringline
• Visual ID: Black sensor box mounted at the end of the wand arm, with a wiring harness running back to the G+/G21 controller
• Part Numbers: Check your Gomaco parts manual for 500-46D83 or 500-46D84
• Connector: 3-pin Weatherpack connector — verify your specific connector type before ordering

Compatible Equipment

Curb & Gutter Machines

• Gomaco GT-3600
• Gomaco GT-3200

Slipform Pavers

• Gomaco Commander III
• Gomaco GP-2600

Trimmers

• Gomaco 9500

⚠️ Verify your connector type (3-pin Weatherpack) matches the connector on your existing sensor. Some older machines or retrofit installations may use a different connector style. Contact us with your machine model and serial number if you're unsure.

Symptoms of a Failing Stringline Sensor

• Paver "hunting" — oscillating left/right instead of tracking the stringline smoothly
• Erratic grade control — surface profile is inconsistent or wavy
• Loss of steering control — paver wanders off the string
• G+ or G21 system displaying sensor fault codes
• Sensor arm tracks the string but the paver doesn't respond
• Intermittent control — works sometimes, fails randomly (often heat-related)
• IRI (International Roughness Index) numbers trending upward
• Grade check reveals inconsistent slab thickness

Why Buy From Trenchwell?

• Under $1,000 — No PO Required: Most superintendents can approve a $985 credit card purchase on the spot. No purchase order, no corporate approval delay, no waiting. Paver runs today.
• Save $500–$800: Gomaco dealers charge $1,500–$1,800 for this sensor. We offer the identical OEM-spec unit at $985.
• In Stock, Ships Fast: Gomaco dealers routinely backorder sensors for 5–10 business days. We have it on the shelf. A paver down during a pour can cost $5,000+ per day in concrete waste, crew idle time, and schedule penalties.
• OEM Specification: Same sealed, vibration-rated, dust-resistant electronics designed for the brutal environment of concrete paving. This is not a cheap knockoff — it's the genuine OEM-specification sensor.
• Keep a Spare: At $985, this sensor should be in every Gomaco service truck. When a wand fails mid-pour, the spare pays for itself on the first use — in saved concrete, saved labor, and saved reputation with the DOT.
• Protect Your IRI: A failing sensor means inconsistent grade control, which means high IRI numbers, which means DOT rejections and grinding penalties. A new sensor keeps your ride numbers where they need to be.

Installation Notes

• Shut down the paver and the G+/G21 control system
• Locate the sensor on the stringline wand arm
• Disconnect the 3-pin Weatherpack connector from the old sensor
• Remove the mounting hardware securing the sensor to the wand arm
• Install the new sensor in the same position and orientation
• Reconnect the 3-pin Weatherpack connector
• Power up the G+/G21 system and verify sensor communication
• Run the standard G+/G21 sensor calibration/setup procedure
• Test with the stringline before resuming paving operations
• Verify grade and steering response are smooth — no hunting or oscillation

Frequently Asked Questions

Will this fix my "hunting" problem?
If the hunting is caused by a failing sensor (intermittent signal, erratic output), yes. However, hunting can also be caused by loose stringline, a bent wand arm, a faulty G+/G21 controller, or incorrect control system settings. If the new sensor doesn't fix the hunting, the issue is upstream — check the string tension, wand arm alignment, and G+/G21 calibration.

What's the difference between 500-46D83 and 500-46D84?
These are variant part numbers that may correspond to different sensor configurations (e.g., grade vs. steering, or different connector styles). Verify which one your machine uses by checking your Gomaco parts manual or the label on the existing sensor. Contact us if you need help identifying the correct part.

Why should I keep a spare?
Because concrete doesn't wait. If a sensor fails at 7 AM on a 2,000-foot pour with 15 ready-mix trucks scheduled, you have two options: (1) finish the slab by hand at terrible quality, or (2) shut down and lose the entire day — the concrete in the trucks sets, the crew is idle, and the DOT pushes your schedule. A $985 spare sensor in the truck eliminates that risk entirely.

Is this the same sensor the Gomaco dealer sells?
Yes. This is the identical OEM-specification sensor — same electronics, same sealed housing, same connector. The Gomaco dealer sells this same sensor for $1,500–$1,800. We offer it at $985 because we source directly from industrial electronics distributors rather than through the Gomaco dealer network.

Do I need to recalibrate after installing?
You should run the standard G+/G21 sensor setup procedure after installing any new sensor. This is the same calibration you'd do after any wand service. Refer to your Gomaco G+/G21 operator manual for the specific steps — it typically takes 10–15 minutes.