I have a 1971 chevelle and the passenger door will not open any help will be appreciated

I had that problem with my 71 back in 99, the latch mechanism inside the door froze up. I had to buy a new one, and replace. They are repoped by most every vendor

http://www.chevelles.com/forums/showthread.php?t=209001&highlight=door+latch

Try this. It is kinda common. Let us know if it doesn't work.

You'll have to pull off the door panel and see if the mechanism is working. Chances are the pushbutton goes in but nothing happens. The lock knob arm could be off and the door really is locked, or Dave and Shawn are onto it.

Thanks one of the latches were off and they needed to be greased up thanks again