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I did some searching on this site and with google, and it seems very possible my flapping/ruddering noise from my HVAC system is some resistor..?? Question is, where is this resistor, does anyone have the part number for it? And how hard is it to replace?

I stumbled upon this earlier, scroll down about halfway threw the page and look at "heater core"....
"Heater core: A clicking noise caused by the heater mode door actuator can be fixed by installing a new resistor in the wiring harness. (1992-94) "

http://consumerguideauto.howstuffworks. ... gacy-6.htm

So can anyone shed some light on this infamous resistor? Thanks!

I have the clicking, but I just ignore it.

Unless there is an easy fix.

( focus on the word EASY there)

There isn't a resistor there from the factory. That page is referring to a kind of ghetto fix that Subaru offered later on. It involves putting a resistor in parallel with the actuator, increasing the current flowing through the wiring harness, thereby increasing the voltage drop through the harness and slowing the actuator down.

The root problem seems to be that the contacts wear out and then sometimes get skipped over. You may be able to resolve the problem by disassembling the mode selector unit and cleaning the copper traces.

If it's clicking and you just want it to stop, you can just slightly press two buttons simultaneously, so that neither of them actually turns on. If no button is depressed, the actuator won't move.

I need a new HVAC control unit...

It doesn't click but it won't go into the highest fan setting. Sorry for the derail.

My car has done this for so many years. Never thought to ask how to fix it. It's not really loud though it just sounds like the actuator keeps trying. Only does it in heat as mentioned.

hmm...maybe i have a unique problem, this is more then just a subtle clicking, its quite loud, and also i noticed it only happens under throttle when the unit is on. Is this what you guys are describing?

vrg3 wrote:There isn't a resistor there from the factory. That page is referring to a kind of ghetto fix that Subaru offered later on. It involves putting a resistor in parallel with the actuator, increasing the current flowing through the wiring harness, thereby increasing the voltage drop through the harness and slowing the actuator down.

is there anymore info on this procedure? how hard is it to do?

I may have a copy of the TSB somewhere around here; let me look and get back to you.

vrg3 wrote:I may have a copy of the TSB somewhere around here; let me look and get back to you.

cool, thanks.