Product Description

8L90 / 10L90 Tap Shift & Reverse Lamp Module

Compatible with: 2014–2018 GM Silverado, Sierra, Tahoe, Suburban, Yukon & Escalade — 5.3L & 6.2L

Newer GM automatic transmissions are fully computer controlled with no external mode switch — all shifting data is transmitted over the CAN bus. While that works great from the factory, it creates a problem when swapping one of these transmissions into an older vehicle.

This module is designed to add tap shift capabilities to your standalone 8L90 or 10L90 transmission and provide a 12V output to power your reverse lamps (up to 10A). It’s a simple wire-in solution that supports multiple input switch types.

⚠ Important: This module simulates the CAN bus messages that the GM BCM sends in a stock vehicle. It is designed to replace the GM BCM on the CAN bus. You cannot have a GM BCM present on the CAN bus while using this module.

⚡ Tap Shifting

Two inputs are provided — TAP UP and TAP DOWN — activated by momentary switches. Select your input type at checkout based on your switch wiring:

• Negative (Ground Trigger): Switch connects input to ground when activated
• Positive (12V Trigger): Switch applies 12V to input when activated

💡 Reverse Lamp Output

The reverse lamp output provides a switched 12V signal when the transmission is in reverse. Supports up to 10A direct load. We recommend using this output to trigger a relay so the full lamp load is carried by the relay, not the module.

🛠️ Installation Overview

Requires splicing into your vehicle’s existing wiring. Basic wiring knowledge required.

• Ignition Switched 12V
• Ground
• CAN Bus High
• CAN Bus Low
• TAP Switch UP Input
• TAP Switch DOWN Input
• Reverse Lamp Output

Includes instructions and wiring diagram.
Download Instructions — Positive (12V Trigger)
Download Instructions — Negative (Ground Trigger)

📦 What’s Included

• Pre-programmed EZCAN tap shift module
• Pigtail wiring harness for installation
• Wiring diagram and instructions

✅ Supported Vehicles & Transmissions

• 2014–2018 Chevrolet Silverado & GMC Sierra — 5.3L, 6.2L
• 2014–2018 Chevrolet Tahoe, Suburban & GMC Yukon — 5.3L, 6.2L
• 2014–2018 Cadillac Escalade — 6.2L

🟢 Select your transmission type and input switch type at checkout.

🔧 Checkout Options

• Input Switch Type: Positive (12V Trigger) or Negative (Ground Trigger)
• Transmission Type:
  • 8L90 — 2014–2016
  • 8L90 — 2017–2018
  • 10L90 — 2017–2018

Have questions or need a custom configuration?
Email us at info@rpmextreme.com