2019-2024 Ram 2500-5500 Towing Control Module: Fixing 'Trailer Disconnected' Errors & Programming a Replacement

Symptoms of a Failing Towing Control Module

When the towing control module begins to fail, it can create confusing and dangerous situations. Because the module controls both braking and lighting, symptoms can affect either system. However, many of these symptoms can also be caused by simple wiring issues on the trailer itself.

Common Failure Symptoms

• "Trailer Brake Disconnected" Message: This is the most common complaint. The message may appear intermittently or stay on constantly in the instrument cluster, even when you know the trailer is securely connected.
• "Check Trailer Brake Wiring" Message: Similar to the disconnected message, this error points to a communication problem between the truck and the trailer's braking system.
• No Trailer Brakes: You may feel the trailer pushing the truck when you brake, indicating the trailer's brakes are not engaging at all. This dramatically increases your stopping distance and is a major safety hazard.
• Inoperative Trailer Lights: The module controls the trailer's turn signals and brake lights. A failed module can cause these lights to stop working, making you invisible to other drivers when stopping or turning.
• Erratic or Weak Braking: A failing module might send an inconsistent signal, causing the trailer brakes to feel weak, engage with a delay, or pulse and jerk instead of applying smoothly.

Known Issues & Recalls

While the 2019-2024 model years do not have a specific recall for this part, Stellantis (Ram's parent company) issued a major recall for the exact same part on newer trucks, which points to a known potential for failure.

NHTSA Recall 26V-059 (For 2025-2026 Models)

In early 2026, FCA/Stellantis recalled over 450,000 vehicles, including 2025-2026 Ram 2500, 3500, 4500, and 5500 trucks, for an improperly designed trailer tow module. The stated defect could cause a loss of trailer brake lights, turn signals, and a complete failure of the trailer brakes to activate. The remedy is a dealer replacement of the faulty module. While this recall does not officially apply to 2019-2024 models, it confirms that this specific component can fail in a way that matches common owner complaints for the earlier years.

CRITICAL: Programming a New or Used Module

You cannot simply swap this module and expect it to work. The module must be programmed to the truck's Body Control Module (BCM) to be recognized and enabled. If you install a new or used module without programming, it will not function, and the gain settings will not appear on your dash display.

Programming Options:

1. Dealership: A Ram dealer can program the new module using their proprietary wiTECH scan tool. This is the most straightforward but often most expensive option.
2. DIY with AlfaOBD: Tech-savvy owners can use the AlfaOBD software (on a Windows laptop or Android device) along with a compatible OBD2 adapter and an SGW bypass cable. This involves manually changing several settings in the BCM to enable the trailer brake controller functions. This is a cost-effective method if you plan to make other customizations to your truck.
3. DIY with a Programmer Tool (OBD Genie): Companies like OBD Genie offer a simple programmer that plugs into the OBD2 port (after the SGW bypass is connected). The tool automatically performs the programming in under a minute and is VIN-locked to your truck. This is the easiest DIY option.

Buying a Used Towing Control Module

A used OEM module is an excellent, cost-effective alternative to a new dealer part, especially since aftermarket versions often lack the seamless integration of the factory system. Here’s what to look for:

• Verify the Part Number: The most current part number is 68413389AC. This part supersedes the older 68413389AB. Always match the part number to ensure compatibility.
• Inspect the Connectors: Carefully check the pins in the electrical connectors. Look for any signs of corrosion (green or white powder), bent pins, or heat damage. A module with damaged pins is useless.
• Check for Water Damage: Inspect the plastic casing for any signs of cracks or warping that could indicate water intrusion, a common cause of electronic failure.
• Budget for Programming: Remember that the cost of the used part is not the final cost. You MUST factor in the expense of programming, whether it's paying a dealer or buying the necessary DIY tools.

Replacement Overview

Physically replacing the module is a relatively simple job that most DIY mechanics can handle in under an hour.

• Module Location: The towing control module is located under the driver's side dashboard, mounted to a metal bracket behind the knee bolster panel.
• Switch Location: The gain control switch is located in the center stack, directly below the infotainment screen.
• Process: The process involves removing the driver's knee bolster and sometimes the panel around the steering column for access. The truck is pre-wired, so installation involves simply unplugging the two connectors from the old module and plugging them into the new one.

Cost Comparison

Note: Prices are estimates and can vary based on location and supplier.

Frequently Asked Questions (FAQ)