AMP Research Pass-Thru OBD Harness | PowerStep Plug-N-Play System | 2018-2026 Ram & Toyota | SKU: 76405-01A

Brand: AMP Research | SKU: 76405-01A | Material: OEM-Grade Heavy-Duty Composite & Copper Wiring | Interface Type: Dual-Port Pass-Through OBD Interface | Free Shipping | Affirm & Afterpay Available

You Installed Automatic Steps. Now Your Diagnostic Port Is Blocked.

You upgraded your truck with an AMP Research PowerStep system to make cab entry effortless on your lifted build. What you didn't plan for was losing your diagnostic port. Standard Plug-N-Play automatic step kits occupy your factory OBD-II port to read digital door-trigger signals. The moment your steps are powered, your OBD port is completely blocked—leaving you unable to plug in a tuner, a digital gauge monitor, or a dealer diagnostic scan tool without manually unplugging your step system.

Worse yet, hacking or tapping into your factory data wires with cheap components introduces serious electrical vulnerability. In high-heat arid climates, low-grade plastic connectors turn brittle and crack under minimal dash vibration. In the high-humidity or freezing salt conditions of the Corrosion Belt, moisture and road brine migrate into unsealed cabin components, causing ghost codes, intermittent step failures, and communication dropouts across your vehicle's Controller Area Network (CAN-bus).

The AMP Research Pass-Thru OBD Harness (SKU: 76405-01A) is the clean, commercial-grade engineering solution. Purpose-built for 2018–2026 Ram and Toyota platforms running Plug-N-Play PowerStep systems, this harness splits your factory port into an integrated, dual-port pass-through assembly. It keeps your automatic steps fully operational while providing an open, fully functional secondary OBD-II port right under your dash.

The Obsidian Take

We carry the AMP Research 76405-01A harness because it preserves your truck's electronic architecture without compromise. Most builders completely ignore OBD port accessibility until their truck is at the dealership or repair shop, and the service writer informs them that their scan tool cannot connect due to step hardware blocking the port. This pass-through harness completely eliminates that checkout friction by acting as a transparent electronic bridge.

Instead of low-tier consumer electronics wiring, this harness features OEM-grade, vibration-resistant molded connectors engineered for severe thermal cycling. Whether you're dealing with a punishing 110°F summer afternoon in Phoenix or freezing winter conditions in the Northeast, the heavy-duty locking tabs remain perfectly secure. It supports simultaneous, high-speed data transmission for both your PowerStep controller and external diagnostic equipment with absolutely zero fault codes or signal degradation. If you run a custom tuner, data logger, or monitor alongside your electronic steps, this pass-through harness is mandatory equipment.

⚠️ Digital Tuning & Monitor Compatibility Note: This harness is engineered to split OBD-II communication lanes cleanly. However, if you plan to run high-frequency, continuous-broadcast data tools (such as specific real-time custom performance programmers or active telemetry loggers) alongside your steps, ensure both modules do not alter the same CAN-bus packet addressing.

⚠️ AMP Research System Architecture Constraints: This pass-through harness is explicitly designed for AMP Research PowerStep, PowerStep XL, and PowerStep Xtreme kits that utilize the OBD-II port for their digital door-trigger source. It will NOT interface with older hardwired step systems that rely on mechanical door magnetic switches or direct analog wire-splicing.

Confirmed Fitment Matrix

CRITICAL FITMENT NOTE: This harness is mathematically and digitally pinned to interface with factory OBD-II communication networks on the specific vehicle platforms outlined below.

❌ This Unit Does NOT Fit:

• 2017 or Older Ram Platforms: Digital communication architectures and physical pinning layouts under the dash do not align.

• Non-OBD PowerStep Kits: Will not function on alternative brand automatic steps or manual hardwired AMP kits.

Technical Specifications

Before You Order — 4 Fitment Checkpoints

Vehicle electrical additions require absolute platform validation. Review these four checkmarks before clicking checkout:

1. Step Trigger Verification: Confirm your existing or incoming AMP PowerStep kit utilizes the OBD port connection. If your step kit hardwires directly into the cab pillars, you do not need this harness.

2. Model Year Verification: Ensure your Ram or Toyota falls strictly within the 2018–2026 window to guarantee correct digital module handshake compatibility.

3. Under-Dash Clearance: Inspect your factory OBD port location. Ensure you do not have aftermarket lower dash panels, custom knee airbags brackets, or center console modifications that physically obstruct a secondary connector seating profile.

4. No T-Taps Rule: Verify your electrical build path. Never use Scotchlocks or T-taps in conjunction with this communication harness, as loose vibrations will cause digital signal flicker and permanent fault codes.

Professional Installation & Mechanical Notes

• Lock Engagement Audit: Pro Tip: When plugging the 76405-01A into your factory under-dash OBD port, push until you hear a distinct mechanical click. Verify the secondary lock engagement tab is completely seated before routing the auxiliary port or powering up your main step controller module.

• Harness Stress Relief: Secure the body of the pass-through harness to nearby factory under-dash structural bracing using heavy-duty zip ties. Leaving the splitter harness dangling freely puts continuous leverage on your factory OBD pins, which can cause connection fatigue over rough off-road washboards.

• Pin Protection: Keep the newly exposed secondary port clear of direct moisture or dirt accumulation during deep floor mat cleanings. A drop of dielectric grease on the housing shell can help seal the interface in high-humidity regional zones.

AMP RESEARCH POLICY NOTE: Because this component integrates directly into a vehicle's digital diagnostic bus network, once the harness has been plugged into an active OBD-II port and powered, the unit is non-returnable per manufacturer safety policies.

Questions We Get Asked

Can I run a custom engine tuner and my AMP PowerSteps at the same time with this harness? Yes. That is exactly what the 76405-01A is engineered to do. It splits the factory OBD-II port, allowing your step controller to pull door-open data while leaving the second port open to power custom tuners, digital accessory gauges, or secondary diagnostic tools.

Does installing this pass-through harness void my truck's factory warranty? No. Because this harness is a 100% plug-and-play assembly that plugs directly into your existing diagnostic port without cutting, splicing, or pinning into the factory wiring loom, it does not void your vehicle's factory warranty.

Will this harness work with automatic steps from brands other than AMP Research? This harness is pinned and mapped out specifically for the data communication pathways and connector shapes used by AMP Research PowerStep, XL, and Xtreme Plug-N-Play controllers. It is not guaranteed to clear or interface properly with competitor systems.

Is any programming required after plugging this harness into my Ram or Toyota? No programming or electronic flashing is needed. The harness acts as a passive hardware splitter for the diagnostic port data lines, making it functional the second it is clipped into place.

Why Buy From Obsidian Forged Auto Supply

• Authorized AMP Research Dealer — Full factory-backed manufacturer warranty protection with factory-direct logistics tracking.

• Free Shipping, Lower 48 — Rapid standard parcel ground delivery directly from our closest regional warehouse.

• Real Fitment Verification — Text (469) 407-7538 (SMS only) with your vehicle’s VIN and your current AMP PowerStep part number. An Obsidian specialist will audit your factory build parameters to ensure a 100% accurate electrical fit before shipping.

• Premium Financing Available — Safe, instant checkout flexibility via Affirm and Afterpay.

Disclaimer

The technical and product information presented above is compiled from data provided directly by the component manufacturer. Obsidian Forged Auto Supply maintains a rigorous engineering audit workflow to ensure vehicle fitment compatibility; however, we are not responsible or liable for sudden manufacturer-driven specification updates, raw metadata changes, or accuracy discrepancies in the foundational data sheets provided by the manufacturer.

2018–2026 Ram & Toyota Tundra / Tacoma. AMP OBD Pass-Thru Harness. Keep your diagnostics open. Add to cart.

Unsure if your digital tuner or custom dash accessory will clear this dual-port pass-through connector path? Text your vehicle setup to (469) 407-7538 and an Obsidian technician will verify it.