How to switch motor outputs and use E1 as X, in Marlin firmware? I broke up my electronics and now the output for X is not working. The stepper is OK. 

There is any simple solution to remap the output pins? I want the E1 output to act as the X output.
When using Marlin firmware you could easily change the pin layout of the extra extruder (E1) with the broken X stepper pins by changing the pins_RAMPS.h file.

Download the firmware and open the firmware project in Arduino IDE. Navigate to the "Steppers" section of the pins_RAMPS.h file and replace:

#define X_STEP_PIN         54
#define X_DIR_PIN          55
#define X_ENABLE_PIN       38
#define X_CS_PIN           53


for:

#define X_STEP_PIN         36
#define X_DIR_PIN          34
#define X_ENABLE_PIN       30
#define X_CS_PIN           44


and also change:

#define E1_STEP_PIN        36
#define E1_DIR_PIN         34
#define E1_ENABLE_PIN      30
#define E1_CS_PIN          44


to:

#define E1_STEP_PIN        54
#define E1_DIR_PIN         55
#define E1_ENABLE_PIN      38
#define E1_CS_PIN          53


When the file is changed an saved, build and upload code to your board and plug the connector of the X stepper into the E1 header.