nexus 5 D820 screen turn off after swiping unlock pattern - solution
 

Just had this nexus 5 with this problem and i just figure it out:
it seems that it is the reading from the Hall IC (magnetic sensor).
i test it by passing strong magnet along the left side of the screen (when the phone face up) while it in sleep mode, this usually turn the screen on...
if it doesn't (like in my case) you have a problem with the Hall IC (U11004).

what you should do is to try to replace it or to bypass it by short the two cap's as i did:

(if you have the chematics it basically short +1V8_VREG_S3A and HALLIC1_INT)
http://s32.postimg.org/3te7k85x1/sol.jpg

Hope i helped somebody.

i had the same problem with two different nexus 5
on the one replacing hall ic fixed it on the other NOT.
Any ideas how to find out which surrounding cap or res is to blame ?

I know I can just short the caps (that woks ! thank you) but I would prefer a real repair. Also I have battery drain problem and wonder if it might be related to the shorted caps or if this idea is stupid and it only can be pm ic

thanks man