My dad tried to replace the window regulator to fix the window and while doing so, did something wrong. The front passenger door on my 2003 Audi A4 1.8 quattro with ≈150,000 miles will no longer open. The lever still works on the inside and outside, but it doesn't do much. I have really looked into it yet but I was hoping I could get some tips or ideas on what the problem could be.

 

Does the power door locks work on the other doors, locking and then unlocking them so they open? Can you hear the sound of the passenger door's latch when doing this? Maybe try the lock-unlock-lock routine to see if the latch loosens up. Otherwise, this might be a case where you need the automotive locksmith. It might be possible to remove the passenger 'door card' panel from within the car, perhaps with the passenger seat moved out of the way first.

 

Just a thought (after you've done 'turbo510's' steps): as you have access to the inside of the car, you could try sliding something thin like coat hanger wire with a hook or loop on the end down the inside of the window and then carefully fish around the latch area and try to unlatch the lock. It sounds like your dad may not have fitted the handle latch bar to the lock and as such the handles do not activate the latch. I did the same job as your dad on my old A6 and it's quite tricky to fit all the latch bars as you reassemble things in there. You could always remove the driver side door card to get an idea where you need to focus your poking around.....