Yes, to reset codes (dash lights on your model), you have to open the hood, find the module and manually put the little pin in the proper holes to force a reset. This is how you clear the check engine light and any other malfunction lights. The module is also how you read the fault codes by counting a series of flashing lights. The car has a very basic built in diagnostic center.
http://www.volvoclub.org.uk/faq/EngineOBDCodes.html
This page will explain the code module - hope it clears the right lights.
If your battery/charging light is still on then I am not sure if this will help but you should learn about the code module anyway.