[9secfirebird]

dude, just replace all the bulbs on the one side, or take em all out and check them, and replace the one that is the worse or the one that doesnt look like its all there. sometimes the bulb is alittle black on the inside, even though its still being lit up, that is a sign of a bad bulb too. when the arrow is on solid, a bulb is ****ed up, its not the flasher. start with the basics. the arrow comes on cuz there isnt enough power passing through one of the bulbs, or a contact isnt touching 100% or something. if it was my car, i would replace all the bulbs for the blinkers (takes like 5 minuets and only costs like 5 bucks) and as i pull each bulb out, bent the little tabs in the socket up abut more to make sure there is a solid connection, then put the new bulb in. i bet thatll fix it.

EDIT:

yes there is a way to check a flasher, its just a switch, use a power and a ground from a 12v source, connect the one pin to a wire going to ground, and tap the other on the positive terminal, it should click. but like it was said, if the flasher is clicking all the time for the otherside, thats prolly not your problem.