2004 Seirra Climate Control

[jebvd]

This is a 2004 seirra with dual climate control.

I have been experiancing this issue for the last month. It started as an intermitant problem, the heat would not work, if I turned the system on and off a few times the heat would start working. A week later I would have to turn the system on and off about 20 times before the heat started working, now I cant get it to work no matter how many times it is switched on and off.

I have tried two things so far, one on the advice of a local tech, I pulled the hvac controller from the dash and unplugged it for a few minutes. Thinking this would reset any hvac settings. I also disconnected the batt to hopefully accomplish the same thing.

Both times when I turned the system on it was defualted to defrost. After awhile all controles worked normall, but still no heat.

While searching this forum I have not found this same problem, It seems that most hvac issues are a problem with one side which could be a blend door actuator. I have no heat from either side, could both blend door motors be bad?

One other thing I noticed, in auto mode, when I turn it on, the A/C (snow flake) is on the control panel. It doesnt matter what I have the temp set on. I dont know if this is normall because I usually use manual control. Is their a cabin temp sensor that could be bad?

Thanks for any and all help!

[gave20]

Well if both actuators are bad it would blow heat all the time, if you take the passenger actuator off you can move the butterfly to the open position and see if your getting heat. If not, then I'd say the heater core is bad.

 

To take the actuator off you need to remove the duct work from the passenger side footwell, don't remove the screw from the center console the whole way or you'll never get it back in. The actuator is up front has a small set of wires hooked to it and looks like a small piano. Before you unplug it turn the temperature to 60 then unplug the actuator and unscrew it from the duct work. You can move the butterfly (square peg) to the open position and that should let heat in or vise versa, I can't remember, either way with the temp on 60 you'll get heat by moving the butterfly if the core is working. Whatever you do don't operate the actuator unbolted from the duct work. You'll over travel the unit and it won't work correctly. Also note you must return the temperature to the same degree that you had when you took the actuator off, if not the system won't work correctly.

 

Your snowflake (a/c) should be on no matter what the cab temp or setting is, as long as the outside temperature is ~36 or above.