If all the bulbs will light high beam on the right, and none will light high beam on the left, then it's not the bulbs. If you're worried about "balance" when testing them, unplug the RH bulb and leave it empty, only hook up the LH bulb. Shouldn't make a difference, but should clear up any doubts about bulbs. Or just buy yourself 2 new matching 9004's.
http://npora.ipbhost.com//index.php?s=&...ndpost&p=99 has the headlight switch/stalk as a common problem.
http://npora.ipbhost.com//index.php?s=&...st&p=272718
DRL module will sometimes cause the headlight on one side to stop working. It hangs just inside the right fender under the hood, a bit in front of the battery. If you turn your lights on, and give this little box a bit of a smack with a screwdriver, the lights may work temporarily. Could be the problem. Reheating all the solder joints to the connectors and relays usually fixes the module for another 5-10 years
Not much else I can tell ya.