My 1991 Volvo 740 wagon 2.3L non turbo has a few issues. I can't diagnose these issues because the OBD box is broken. Is there any place I can buy one of these? I have tried looking for one but I can't seem to find it.
I don't understand, are you talking about the OBD diagnostic plug or are you talking about the computer.
If you are inquiring about an OBD reader you can get a fairly reasonable one at your local auto parts store or Auto Zone auto parts store.