NEED HELP Need some HVAC Help

tony blais

New Member
Could use a little help with the lower vents intermittently working on the family, (wife's) '04 TB with auto HVAC controls. Sometimes when cycling thru the mode selector, the actuator would work, but naturally for her, she is not getting any heat at floor level.

I've spend an hour looking through the old Trailvoy posts on HVAC actuator failures after replacing/disconnecting the battery, have not really found anything pertaining to a intermittent mode actuator problem. Perhaps it's a control problem?

Any response would be appreciated.


Platinum Supporter
The problem with the actuators is that the cheap plastic gears/teeth eventually break. Especially after you re-hook the battery if you had to disconnect it for whatever reason. The actuators go through a sweep and self test after the power is reconnected. These quick actions can break the teeth on the gears. The blend door actuator that she has failing is the one that controls air flow direction. Unfortunately this actuator is the most annoying to replace and because it's very hard to reach with anything, but a micro socket wrench. And your body is gonna be all sorts of contorted trying to replace it. But with a little effort you'll get it out and a new one in. It's just time consuming because there's very little room to work in.

Here's a few threads you can look through to get an idea of how you need to go about replacing that actuator. I seem to be the guy that comes flying to the rescue with answers on this issue.


Well-Known Member
What Capote described is what happened to my mode door actuator and a big PITA to change.

You can see the large plastic gear at the top is missing two teeth. Also the broken teeth caused a clicking sound by the actuator.



Platinum Supporter
Unfortunately this is a very common thing. It's wise to keep spares around just in case. Every actuator is different by the way, you need the "Blend Door Actuator" though in your case.


Lifetime VIP Supporter
This initial re-set procedure can work sometimes after a battery replacement to properly re-calibrate the HVAC Actuators... if that fails to solve the problem or actually reveals a broken one, this Dude describes the correct R&R procedure for more than one actuator and visually amplifies on what @dmanns67 mentioned for solutions above... if there are multiple actuator failures involved. The Dude here solves an additional problem with a very clever repair:

This video covers the Blower Resistor Testing and R&R by the same OP:

And if the Blower Motor WILL NOT TURN OFF and runs the battery flat... this repair works and he works out his own personal problems with his very own "VENT" that is entertaining as well:

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I only had problems with fan speed.

tony blais

New Member
Thanks for all your replies, I'm confused that if the actuator drivetrain has failed why is it intermittent, meaning that the lower vents will sometime work? My son seems to think that the controller is the problem, as he says sometimes if an attempt is made to change the temperature, the controller will not respond.

Perhaps there are multiple HVAC problems going on?


New Member
having issues with driver side temp changing to cold air when the heat is on. it will start off ok then switch to cold air coming from the vents. and it seems no matter which mode i choose air comes out dash as well as where it is supposed to. it doesn't come out forceful anywhere even when the fan speed is at max. I can hear it blowing fast but just not coming out fast. I just did the reset twice and heard it go through it's paces but still have the same air movement but now it shows the outside temp being 61 when it is actually 37. both times resetting it started off with the AC on and showing outside temp of 71 then drops down to 60's. could this be an issue with the control panel? I have the electronic climate controls.


The panel rarely fails. It's usually a dead actuator, in this case, the mode actuator. Not in all cases they will do the clicking sound when it fails.

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