Nissan Repair: 91 maxima wipers, vacuum motor, vacuum line

Question
i am having a problem with the wipers. sometimes they work and the rest of the time they don't.i can tell right away if they'll work because the clock will be working then too.also heater only works for defrost.what do you think? thanks

Answer
Larry,

Sounds like the ignition switch is not returning to run after you start the car.  Check to see if the key returns and that might be the cause of the problem.  From memory, there is not a relay that drives the interior accessories so it has to be the ignition switch.  The heater, if it does it all the time, would be the control panel or the blend door actuator motor.  From memory, on a 91 Maxima it is a vacuum motor and if it fails it stays on defrost for safety.  You can remove the center section of the dash to gain access to the door.  Removing the glovebox aids in the process.  What you are looking for is a little can with a vacuum line on one end and an actuator arm on the other.  You can move the arm and note the change in the air and if it comes out the registers, floor or defrost.  Then, take a vacuum pump and draw a vacuum on the line and if it moves and works then you either have a bad vacuum hose, connection or the control panel itself.  If it does not move with vacuum applied replace the vacuum motor.