The same motor in the code, won’t work on the drivetrain

We’ve been having issues with motors not working on our robot. After some testing, we realized it’s not a due to a bad wire or port, but the same motor in the code, won’t work. Our back left motor is plugged into port 14, and doesn’t work. When you switch the cables so that port 14 goes to front left, and the cable that’s plugged into front left goes into back left, the back left motor starts working, but the front left motor won’t work anymore. We’ve tried switched ports and cables around lots of times, and have re-uploaded the code, but we keep running into the same issue. What should we do?

Some additional information is usually helpful in this, like which programming environment you’re using (VexCode v5/VexCode V5 Pro/PROS), and any relevant robot configuration/setup (like screenshot of robot port setup if using VexCode, or PROS device definitions).

This sort of info can help folks help you figure out what’s going on. Also, surround any code snippets with three ` characters so that it formats as code.

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Assuming you are absolutely sure it is not your code (try in any order):

  1. On the brain - Settings | Delete Programs. Load your program then try again.

  2. Set up a drive train and controller - motors and controller only. Add no additional code and upload it to the brain. See if that activates the motor as normal. If so, reload your original program and see if it works.

  3. Create a new program with your motors and controller only - no drive train. Code the motors (drive code) to activate forward and reverse on some controller input (doesn’t matter). It should be very simple. Load this program. If it behaves as expected, reload your original program and see if it works. If not, repeat with blocks/V5 if you used Pro or repeat with Pro if you used blocks/V5.