You could try my glcd tester.... [github.com]
No setup required, so you cant get it wrong.... (so don't change anything!)
There are many possible causes
Most probable cause is your lcd cables are to long (only works with short cables)
Or you haven't formatted the sd to fat16 or fat32
Or the sdcard just does not support the required SPI protocol (newer high capacity cards often lack this) (you didnt mention brands or sizes)
No setup required, so you cant get it wrong.... (so don't change anything!)
There are many possible causes
Most probable cause is your lcd cables are to long (only works with short cables)
Or you haven't formatted the sd to fat16 or fat32
Or the sdcard just does not support the required SPI protocol (newer high capacity cards often lack this) (you didnt mention brands or sizes)