a1502 trackpad not woking

[Nick]

hi got an a1502 820-3476 that had wd trackpad. customer replaced it but it didn't work. i tried another one and same, tried a known good one from another machine and still doesn't work. the button works fine. keyboard works fine. cable is brand new. no oxide on the motherboard and anywhere else beside the trackpad. what should i look for?

 

[2informaticos]

Did you try known good cable too?
Keyboard not working too.
Disconnect keyboard and check trackpad again.
Try to acces boot menu, let see if something works.

Check voltages on L4807, R4808, U4801 and J4800.
Check continuity betwwen J4800/U4801.