I have a 90 legacy AWD 4EAT and when I got the car I noticed that it was stuck on heat and when you clicked anything else you could hear it clicking as if it were trying to move something but was stuck on something. Somehow this eventually fixed itself a month or so later.

 

Anyways, it's back again and it's annoying. Can this be lubed or something or does it need to be replaced? If you stick your hand down there under the driverside dash and manually push the lever, it stops clicking and opens/closes the vents accordingly.

It's probably in the electronics. There are soldered joints in the HVAC unit that crack and cause intermittant issues. The unit can be removed and fixed if you're handy with a soldering iron.

 

Check out the "HVAC butttons don't work all the time" sticky in the body & chassis forum on www.bbs.legacycentral.org for more info & pics.

 

Josh

depends which mix door it is. Some of them are motors some are vaccume operated. The clicking is the door motor not knowing to shut itself off. You need a new door motor

 

nipper

same with my car, u know what though, i took out my glove box, and tightened the screw for the vent door motor, and my mom drives the car all day, and she said there is NO knocking anymore, the screws weren't loose, but they werent tight either, like there were tight, but then it slipped the screws, and it pulled further in, but even when my car was new, it still had this problem, but my dad said it never did it when he brought it to the dealer, now its gone, lol, but my dad said its a pneumatic system, its a motor though, for a pneumatic door, shouldn't keep banging.

same with my car, u know what though, i took out my glove box, and tightened the screw for the vent door motor, and my mom drives the car all day, and she said there is NO knocking anymore, the screws weren't loose, but they werent tight either, like there were tight, but then it slipped the screws, and it pulled further in, but even when my car was new, it still had this problem, but my dad said it never did it when he brought it to the dealer, now its gone, lol, but my dad said its a pneumatic system, its a motor though, for a pneumatic door, shouldn't keep banging.

 

i wasnt sure if it was a vacume system, electric or a mix of both.

 

nipper

Anyways, it's back again and it's annoying. Can this be lubed or something or does it need to be replaced? If you stick your hand down there under the driverside dash and manually push the lever, it stops clicking and opens/closes the vents accordingly.

I would work all the rotation points and move things manually to hopefully get things aligned under there. My car would do the same thing on occasion when it was really cold. Ever since I had to replace the heater core (subsequently pulling of all the HVAC stuff out and putting it back in) the noise has disappeared.