S13 Driver Window Rolls Up But Only Sometimes Down. Searched, Tryed Amp&Switch. Help!

[LJBS13]

i have a 92 240sx. i've been having an issue with my drivers side power window. the window will roll up just fine, but it will not roll back down. i have pushed the windows up and down switch buttons back and forth playing with it and every so often it would work just for 1 time to roll the window down. now the window is just stuck fully up.

I plugged in a working switch and a working amp and both did nothing. now when i press the up button i can hear the amp click, when i press down nothing. i also tested power to the motor, when i hit the switch up i'm getting power, when i hit the switch down the wires show no power, i tested both wires going to the motor. i cant find a straight answer on exactly how to further troubleshoot my problem i'm assuming i need to supply power directly to the motor to check if it is working still, if so can anyone chime in on the correct wires to tap in to or the proper procedure? Is the any other connections i can check? any info is appreciated

[Vegass13]

i would unplug the connector to the window motor and apply 12v directly to one prong and ground the other one way the window should go up, flip it around it should go down. if it goes up and then you swap the power and ground to opposite wire and it doesn't go down then I would say you need a new motor...if it does go down then you know which wire to trace

[SlpAngl]

Same thing happened to me, I pulled the amp out & checked the board & found a solder point with a little bit of a crack. Re soldered it & it worked fine. First thing to check would be pull your amp & check the board, while you have it out clean the contacts too.