BMW Repair: BMW325i1992left rear door window glass, mechanic shop, window switches

Question
I am having problem with my 1992 BMW325i left side rear window glass. It works sometimes after pushing the switch several times. I changed the switch (both) still it seems does not work. Recently I changed the window regulator and door stoper at a local mechanic shop with orginal OEM parts. Anyone can help me to solve this problem. Thanks  

Answer
If you changed the window motor and it still does not work then take a tes light and probe the power wire on the window motor.  While pushing the window switch on and off, check to see if the test light lights up.  If it DOES light up, then you know your window motor is not working.  If it DOES NOT light up then you need to start tracing your wires and looking for shorts, blown fuses etc...because you are not having power going to your window motor.  Also use the test light to check for power going into your window switches and comming out of it. Check the ground.  Hope this helps.
Let me know how it turns out.  
Rahim..