Whether a spacecraft ends up being hot or cold in a vacuum (which is a perfect conductive and convective insulator) has a lot to do with the radiative balances on it's surfaces, and the wavelengths being emmitted and absorbed. (And the amount of heat being generated internally).
You can have a sunward facing radiator on your spacecraft, as long as it reflects wavelengths in the visible regions where the sun is putting out the most energy, and absorbs (is blackbody) in the infrared regions where the spacecraft, due to it's temperature, will be radiating.
If your spacecraft was painted black, it would get pretty dang hot, even with no internal heat sources. If it is very reflective in the visible and near-infrared range, it'll get very cold.
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