Intermittent Wipers work sometimes

I have been having a problem with my intermittent wipers ( all other wiper functions operate as normal)... sometimes it is a very brief delay(1 second), sometimes it completes a "double-wipe", and sometimes the delay is 30 seconds or doesnt work at all. Is there a relay (potentially faulty) that controls the wiper delay? Could that be the problem? Or could it be just a bad contact somewhere? I've had my '94 C220 car for a month and just noticed this problem because it hasn't really rained around here for a while. Thanks in advance for any tips.