Reseated G Shield to Arduino and only Z Limit switch works

[LarryM]

Check this thread to learn how to talk to Grbl. Once that’s done, enter the command $$ and it will output the Grbl parameters. Post them here.

Using Grbl - Direct Communication

Direct access to grbl. You can interact with grbl directly to isolate problems at the low level. To do so, you need to use a terminal type program to issue commands and get responses from the serial port that has the Arduino attached. Some of the programs are HyperTerminal, Putty, UGS (limited access), and the Serial Monitor in the Arduino IDE, among others. Make sure that you have the correct settings for the program that you use. The COM port where the Arduino is attached should have the …

Here’s a tutorial for installing the Arduino IDE.

https://learn.sparkfun.com/tutorials/installing-arduino-ide

Do not load the blink program it will erase Grbl.