HVAC not switching from vent to any other mode

Tiny
SRELLIOTT86
  • MEMBER
  • 2006 DODGE RAM
  • 4.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 130,000 MILES
Mode 1 actuator went out so I replaced it and it would switch modes very slowly and finally quit working after about 5 minutes and stayed on middle vents. Cleared all codes and ran an actuator test and still no change. Shows codes on all actuators now. Replaced control board/selector switch and still no change. Pulled all fuses, disconnected battery, and let sit for 20 minutes and it still won't change. With the motor off but key turned on I can hear the actuators moving but does not change directions.
Monday, March 7th, 2022 AT 5:31 AM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

It sounds like either there is a low voltage issue to the actuator or the door itself isn't moving easily.

With the actuator removed, are you able to freely move the door?

Also, I attached diagnostics for low voltage below. Take a look through them and let me know if it is something you feel comfortable doing. Additionally, if you have a scan tool that can read can-bus codes, check to see if there are any B codes stored.

Let me know.

Joe

See pics below.
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Monday, March 7th, 2022 AT 6:31 PM
Tiny
SRELLIOTT86
  • MEMBER
  • 3 POSTS
Yes, the door moves freely and I have checked the voltage as well. No B codes was found.
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Monday, March 7th, 2022 AT 6:41 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

What voltage was found? Also, did the voltage change when changing the airflow direction? If it was and was within spec as far as the voltage, then we need to consider a bad connection, a weak ground, or the control unit is faulty.

I attached a portion of the wiring schematic below. Check to make sure the grounds are good. Make sure the connector at the actuator is not damaged or corroded.

It sounds like one of the circuits isn't able to keep up with the demand. Let me know if there are any other controls that are not working properly.

Let me know what you find.

Joe

See pics below.
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Tuesday, March 8th, 2022 AT 1:06 PM
Tiny
SRELLIOTT86
  • MEMBER
  • 3 POSTS
Thank you for all your help but I pulled the dash and the whole HVAC unit today and what I found was that all four doors were broken. Actuators are performing as they should but being the doors were broken, it wouldn't change directions. All plastic doors in these systems. Replacing with aluminum. Talked to a few mechanics and apparently when one actuator goes out it screws with the rest of them. The codes I was getting when I performed the actuator test was all actuators failed. Door travel range too far.
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Tuesday, March 8th, 2022 AT 1:31 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

Thanks for letting me know. Honestly, anything to make things more interesting.

Regardless, please feel free to come back anytime in the future if you have questions. You're always welcome.

Take care,

Joe
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Tuesday, March 8th, 2022 AT 2:05 PM

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