My iphone screen light not working but everything else still working fine

Phone 3gs has additional accessiblity functions like ‘voice over’
This function gives u addtional use of iphone with tapping by using two and three fingers
Tap three fingers three times on your iphone screen. It will deactivate the screen curtain and your screen will display as usual.
If not resolved try resetting your iphone by holding down home and sleep/wake button for 10 seconds..
if still not resolved restore your iphone using itunes…..before restoring ALWAYS make a backup. If these steps do not resolve the issue, there is a good chance that the backlight has go out. I hope this helps you! Good luck and please vote if this helps.

There may be your iphone lcd screen hardware failure, it is recommended to professional look after sale to. If you need to replace, I suggest you can go to this site to seek help! iphone parts samsung parts iphone 6 parts YDT parts

Hi can anyone help please, i have a iphone 3gs its been working fine, till i have changed the lcd (screen) now we have changed many lcd in past for iphones no problems whats so ever.
These lcd were tested on different iphones and there worked fine.
I have tryed different lcd in this iphone 3gs still the same problem, ' no back light' ive checked the brightness thats fine, ITS not Liquid damage whats so ever.
can anyone help me to solve this problem please????