My 92 honda prelude has the same problem and I will change Main Relay(I am ordering now. it costs $65 ). I think supernova right because I read the information from the sites below:
http://autorepair.about.com/library/diy/bl_hmr-1.htm
and
http://www.markl.f9.co.uk/howto/elec...main-relay.htm
If the admin of this site not allow to post anylink on the forum please accept my apologize and delete the post thank you