Hot or cold air.

I posted a question about my heater air temperature problem a while back and got some advice at the time. But I never got under the dash to take a look at it. Well now I finally did while fixing a separate electrical problem. When I turn the temperature control from hot to cold it only sends two signals to the damper control. Either open all the way to hot or all the way to cold. At exactly the (vertical) halfway point of the dash knob if you turn it one click to the right it's hot, and one click to the left it's cold. Nothing in between. I see the motor that controls the damper is electrical, not vacuum. I can see the motor turning (obviously). Do the symptoms I list above point to the dashboard control as being the problem or the motor that drives the damper. Thanks for any help.

I did some further investigating today and found the following. Everything seems to be ok with the control in the dash. All wiring checked out ok. When I tested the voltage at the wires that go into the unit that moves the mixer door I got these results. If anyone can verify these are correct please do. I will take this info to my Chevy dealer to see if they will verify I need the motor.

This was all done with a DC voltmeter:
Black wire negative and brown wire positive, constant 12 volts. Can verify this with the wiring diagram.
Black wire negative, light blue wire positive, gradually to 12 volts when moving the dash knob to cold.
Light blue wire negative, brown wire positive, gradually to 12 volts when moving the dash knob to hot.

All voltages increased or decreased very smoothly when turning the knob.
And also the motor is turning but only to full open or full closed (see my first post).

sounds like position sensor in temp door actuator went bad. needs actuator for temp door

Yep, that's what it was. Picked one up this noon from the Chevy dealer and installed it tonight. It took about 20 minutes to change, kinda awkward getting at it, and saved around $80 ~ $100 in diagnostics and labor. Gotta love it.:lol: :grinno: :grinyes:

Yep, that's what it was. Picked one up this noon from the Chevy dealer and installed it tonight. It took about 20 minutes to change, kinda awkward getting at it, and saved around $80 ~ $100 in diagnostics and labor. Gotta love it.:lol: :grinno: :grinyes:
Way to go on the troubleshooting and repair! Excellent work!

Take Care,

Thanks for the complement :wink:

Congratulation buddy that is awesome. Got a simmilar issue with my Venture 2001. When turning the temp control knob from blue to red the air flow reduces to about 1/3. If I bring the knob back to blue without disturbing any other controls, flow increases back to normal. In nother words AC works great but Heater Air flow is restricted and the air is not that hot. Please advice.:banghead:

How can I find the way to remove the Dash to get access to the heater?

On both the passenger and drivers side there are panels (gray colored in my van) under the dash you need to remove. They use those typical Christmas tree fasteners and there may be wires and courtesy lamps attached to them. On the passenger side it really helps to remove the glove box, it's easy to do. Actually you must remove the glove box if you want to view the various electric and vacuum motors that control the temperature and direction of the air flow. Once all the stuff is removed watch things move as someone else turns the knobs on the dash. Have them tell you what they are doing as they make changes. You will begin to understand what motors control what dampers and hopefully be able to diagnose the problem. It helps if you have a manual. I've used the Haynes manual for most of my repairs and it has never let me down. Let us know what you find.

Congratulation buddy that is awesome. Got a simmilar issue with my Venture 2001. When turning the temp control knob from blue to red the air flow reduces to about 1/3. If I bring the knob back to blue without disturbing any other controls, flow increases back to normal. In nother words AC works great but Heater Air flow is restricted and the air is not that hot. Please advice.:banghead:

How can I find the way to remove the Dash to get access to the heater?

I have this same issue. Didi you figure it out?