iPad is showing extremely light visual

I have replaced 2 digitizers on 2 different Ipad2s, both acted just as you describe after installation. The first one just started working after about 24hrs. The second continued to be faint. I read the post about rechecking the lcd connection. I didn't want to remove the new digitizer if I didn't have to. So I took the impact method. I lighty bounced my ipad edges on my desk. It must have caused the connection to connect, because it started working. I know this is not high tech and stress lightly bounced ipad. Try at your own risk. I would bounce on hard surface, such as a table top, desk etc. so it gives the ipad a sharp jar.

The power button must have to be fully working in order to make any hard reset or putting device in to DFU mode. If possible you can open it up again to make sure that all connectors are properly plugged in or not. If by doing all this and increasing brightness still keeps your LCD dim then you may need to replace the LCD.

Try lifting the motherboard from the battery contacts for a few moments and then reseat it again ....sometimes I think this discharges static or just makes a better contact. Make sure power is off and to be safe disconnect the cable from the daughterbd ( comes across between the battery segments). This has worked for me on several repairs.

Good luck!