You shouldn't need harness to CHECK hids. Just connect ballast to light connector, leave bulb in plastic protection surround and switch on the lights. If it's not lightning up, put plug which is coming onto light connector other way around. That's it really...
Ballast should at least give some buzzing sound at start, even if bulb is not catching up. If you want to try harness, you can get one for like 7 pounds from e-bay. What indicating you to "I do not need harness" idea? Harness is really used in first crucial (and most wanted by you) moment, when bulbs are getting a LOT of current to warm up. This phase take around 4 sec and after that they drop down to normal. People installing harnesses, when standard built in car system cannot handle additional power drain and simply do not lit up bulbs Harness allow you to drain power staright from battery, bypassing Supras light system (which is kinda delicate and crap).