Air door actuator fault

Tiny
RHDSTS
  • MEMBER
  • 2003 CADILLAC SEVILLE
  • 4.6L
  • V8
  • FWD
  • AUTOMATIC
  • 32,000 MILES
Passenger air door actuator does not respond to HVAC controller commands. It stays in the hot position.
I have a GM Tech 2 scanner. When I select a cold temp (15C) the passenger air door voltage readings fluctuate (0.61v-4.83v); when I select a hot temperature (32C) it does not fluctuate (stays at 0.61v).

I tried to re-calibrate the actuator doors (several times now). The passenger air door does respond, cycling through its range.

The air door also does respond to the TEch 2 command to hot or to cold, except it does the opposite of the command.

The Tech 2 is showing the solar sensor readings as unchanged at 235 counts, whether covered with a black cloth or when allowing daylight to shine on them (or about 4.63 v, when changing the readout to volts). I tried unplugging the sensors; each time the voltage went to 5.00 v on the Tech 2.

I replaced both solar sensors with new ones. It made no difference.

I have tried two other used HVAC controllers. No difference, except for one of them, the actuator appeared to respond to commands in the lower half of the temperature range. It did this only once. Despite repeated attempts to replicate this, I could not.

Checked voltages from the HVAC control model to the pass air door actuator and then wiring resistance. Both appeared to be within correct parameters.

Vent temp sensors appear to show the correct temperature.

No codes present, except at first when I bought the car. A previous owner had removed the passenger air door actuator altogether (obviously they could not fix the problem so removed the actuator)
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Sunday, June 4th, 2017 AT 12:32 AM

5 Replies

Tiny
JIS001
  • EXPERT
Majority of the times the temperature blend door actuator is what fails. You need to remove the actuator and manually move the blend door from cold to hot with the vehicle off. If it moves freely then replace the damper motor. If it does not move then the whole climate box will need to be replaced.
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Sunday, June 4th, 2017 AT 3:12 AM
Tiny
RHDSTS
  • MEMBER
The air door actuator is new. It works when commanded by the Tech 2. Also, there is no restriction of movement in the door itself.
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Sunday, June 4th, 2017 AT 3:31 AM
Tiny
JIS001
  • EXPERT
Have you checked your grounds also for high resistance?
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Sunday, June 4th, 2017 AT 2:03 PM
Tiny
RHDSTS
  • MEMBER
Yes I have. I also unbolted the ground at the door frame to make sure that it wasn't corroded. It was fine. The only things that I can think of that might cause these symptoms is a faulty Dash Integration Module or possibly the HVAC control module (yet I have tried two other HVAC control modules, neither changed the symptoms except, as I said earlier, the first one, and only once). I got some electrical contact cleaner and sprayed it on the loom plugs for the air door and the DIM. Next I will try the plugs for the HVAC control module. Other than concentrating on the HVAC control loom plug for a possible short or high resistance (I have already checked this, but will again) a replacement DIM seems like my only other option.
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Monday, June 5th, 2017 AT 12:37 AM
Tiny
KEN
  • ADMIN
Hello,

Yes the DIM sounds like it is bad.

Please let us know what happens, we are interested to see what it is.

Cheers, Ken
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Wednesday, June 7th, 2017 AT 9:10 AM

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