Nissan Repair: Vibration or Buzzing sound, nissan truck, fan motor

Question
I have a 87 Nissan truck.  Theres a vibration or buzzing sound that can be felt on the evap. box. Do you know what is causing it, or what I can do it fix it? Thanks.

Answer
Karlyn,

Is the vibrating or buzzing related to the fan motor running when the air is on?  If the noise and buzz are flet and heard when the fan motor is running then your fan is going out.  It is not too common for the expansion valve to make noise so my bet is the fan motor.  It probably needs to be replaced.