2000 Honda Accord EX v6

So I think I have a connection or resistance problem. 2 months ago i changed my alternator and everything was fine. recently the battery light came on, so i pushed down on the green 4prong alternator plug and it went away. when I got home i noticed if the 4P is loose the battery is 12.5 when the car is idle and on (also turns on battery dash light). and if i move the cord slightly it changes to 14.5 right away.
is it the cable or could something else be the problem?

as for resistance when i put my multimeters negative cable on the outside case of the alternator, and the positive cable on the negative battery post, it reads 5-6 volts, is that because of the cable? or something else?

also, since then my d4 light dims intermittently when i'm driving. and when it dims the power windows are really slow.


Battery car off is 12.5volts
Battery car on idle is 14.5
Alternator voltage reading is 14.7

any help would really be appreciated.

 

test the new alternator. if it is ok then the cable might be loose or the connector on the cable or alternator has a short/malfunction

 

the alternator tested fine on autozones battery load tester. it also is 14.7v

how do i test the cables? can i test them with a multimeter?