integry tranny probs

hey guys i have a problem...i own a 90 integra gs...it has an auto tranny...and abut 202*** km on it...the prolem is that at times when i do put the car in park.. the park light on the dash which shows that the car is in park... does not light up...and because of this i cannot remove the key or even shift the gear...normally it comes back on when i play with it or wait about 6 minutes and then i can shift frm park to reverse etc.....help?:banghead::banghead: