**One-by-One E-Bike Controller Replacement: Step-by-Step Guide**

**Before You Begin:**
- Ensure the e-bike is turned off and not connected to any power source.
- Have the new e-bike controller and necessary tools ready.

**Step 1: Identify and Document the Connections**
1. Take clear photos of the existing e-bike controller's wiring connections. Ensure that each wire's color and location are clearly visible in the photos.

**Step 2: Replace Wires One by One**
1. Begin with one wire at a time. Identify the first wire you want to replace.
2. Gently disconnect the first wire from the old controller's terminal.
3. Connect the corresponding end of the same wire to the terminal on the new controller in the same location.

**Step 3: Repeat for Remaining Wires**
1. Proceed to replace each wire, one by one, following the same process as in Step 2.
2. Match the wires according to their colors and positions as shown in your photos.

**Step 4: Test the Connections**
1. Turn on the e-bike and test the functionality of the throttle, brakes, and other features controlled by the controller to ensure everything works as expected.

**Step 5: Final Check and Secure the Controller**
1. Double-check that all connections are secure and properly attached.
2. Ensure there are no loose wires that could cause interference or safety issues.
3. If satisfied, securely attach the new controller in the same location as the old one.

**Step 6: Inform the Customer**
1. If you're providing these instructions to customers, emphasize the importance of following the one-by-one replacement process to maintain proper wiring order.
2. Remind them that if they're unsure at any point, it's best to consult a professional bike mechanic.