If you take it out or at least get a good look at the resistor, it has a series of colors on the resister that will tell you the values. The color of the resistor itself will also yield additional information.
That is all I know. I see them in blue and a brown/cream color mainly. Using the colors, you should be able to find some sort of site on the internet to tell you the values. This site may help:
Resistor Color Bands
Hopefully this is of assistance for you. Usually these are super cheap and often readily available. Only bad thing is sometimes you have to buy a bunch of them. Oh well, having spares is good.