AC only works on coldest setting?

[I6CJ7]

I did search this first. But my issue seems different than most.

EATC controls (digital readout temp)

When I first got this 2000 mounty, it had the clicking noise with the hvac like the blend door actuator gear had stripped (this truck hasn't had much if any use for a long time by a little old lady)

I ordered an actuator. But after driving it for a week without wanting to touch the controls it finally got warm enough to want AC.. Now it doesn't make any clicking noises like the gear isn't stripped? All my fan speeds work. But ac only works set to 60f (coldest) if I bump it up even 5f it will start to blow hot air. If I select vent: - hot only.... max ac works, but also all fan speeds. It just won't work on blend settings for different temps.

Is this the hvac control unit out under the blower motor?

 

[amj441]

under the blower motor is the blower motor speed resistors. this only controls fan speeds. if all fan speeds work, then that resistor pack is fine.

You mentioned clicking and I would assume the internal gears have stripped and have hopped out of calibration. you may need that blend door actuator. or at minimum re-calibrate the blend door with a scan tool.

Additionally check to make sure that your heater control valve moves when you use max a/c. it should apply vacuum and close the valve cutting heat to the heater core. this should help keep the a/c cold.

 

[I6CJ7]

under the blower motor is the blower motor speed resistors. this only controls fan speeds. if all fan speeds work, then that resistor pack is fine.

You mentioned clicking and I would assume the internal gears have stripped and have hopped out of calibration. you may need that blend door actuator. or at minimum re-calibrate the blend door with a scan tool.

Additionally check to make sure that your heater control valve moves when you use max a/c. it should apply vacuum and close the valve cutting heat to the heater core. this should help keep the a/c cold.

I actually have a very nice Autel scan tool. That can perform all kinds of functions. I haven't had it long enough to know all it's features. Any idea how to go about re-calibrating the blend door? I'll check that vacuum valve, that was in my mind as another possible problem

 

[I6CJ7]

I used the scan tool and it tried to do the re-calibration for the EATC. The display on for the temp does a little animation. But the clicking started immediately and went on for about 2 min. Threw the code DTC B1249. Blend door actuator

 

[amj441]

I used the scan tool and it tried to do the re-calibration for the EATC. The display on for the temp does a little animation. But the clicking started immediately and went on for about 2 min. Threw the code DTC B1249. Blend door actuator

yes, so the calibration monitors the blend door actuator as the door moves from one extreme to the other (max cold to max hot) If that gear is stripped that bad, it may not recieve the desired measured resistance when it hits that extreme so the motor keeps turning resulting in the clicking sound. Un-fortunately looks like you might be doing your blend door actuator.

(or try the hot cold now and see where it sits, it may be more "centered" and cold and hot may be in a more favorable position)

The blend door actuator seems to be visible in this video, please do not cut a hole in your a/c box.

 

[I6CJ7]

Just to update, I got the blend actuator motor swapped out and recalibrated it with the scan tool first. Then learned you can hold off/defrost? As i recall from a video, I'll double check. To activate its own recalibration mode. Where it'll do a test for 30 seconds, then show a full lit screen with all functions visible, to signify no faults were found and it's good to go.

It was cold today, so I only used the heat. But the temp, fan and vent/blend settings all did what were told.

I was able to get the rear 3rd screw out from behind the motor through the glove box... And I can say that's something that probably 98% of people are gonna need to hire a small primate to do.. It's still a miracle I didn't drop the screw back there both times. I used a 1/4 socket and the shortest 8mm socket I had.

I feel like a 1/4" 8mm - flex head wrench with the little 1/8" or so extension lip from the socket, along with a handle that's at least 6" would make this doable for average people. Along with a magnet to catch it.

Lining up the motors shaft to the blend door wasn't fun either.. I used my phone to get a picture of it's orientation so I could attempt to key it right.