Console Mode Actuator Problem?

[cmatt]

Trying to figure out if I have a problem with another HVAC actuator. Can anyone verify what modes would activate the center console actuator on my EXT with auto A/C? When I select different modes at the auxiliary HVAC control module for the rear, I'm getting very little air flow from the vents that are located at the bottom rear of the center console.

 

[The_Roadie]

Does the fan change speed when you change its button control? Does the airflow change from floor to the upper console vents when you fiddle with the mode control?

The only controls that affect the console airflow and speed are the buttons on the back of the console. The temperature is set by the passenger's side FRONT temp control.

 

[cmatt]

Does the fan change speed when you change its button control? Does the airflow change from floor to the upper console vents when you fiddle with the mode control?

The only controls that affect the console airflow and speed are the buttons on the back of the console. The temperature is set by the passenger's side FRONT temp control.

Yes, the fan speed does change. The airflow also does change (speed and position) from the roof vents and I can hear/feel it coming from the 3rd row floor vent, but there is very little airflow from those two lower vents at the rear of the center console. Almost like the actuator isn't moving the door. To be honest, I did even realize there was one there, but it appears there is according to the info from AllData using my VIN.

 

[The_Roadie]

I'm sorry. I get confused sometimes about the EXT systems because I don't have one. The trick is usually that the front aux blower control switch has a confusing control design. If the switch is in the REAR position, then the control buttons at the back side of the console exert control over the blower speed and airflow mode of BOTH the console and the way back system, and the temp. If the front switch is in 1, 2, or 3, then the rear console buttons do nothing, and the rear (aux) system's temp mimics the passenger side front temp control, and the airflow mode (ceiling or floor) mimics the front mode. Your console actuator could certainly be dead. If you want to dig deeper with a voltmeter at the actuator, let me know and I can post a schematic.

 

[cmatt]

That would be great, thanks.

Oh, and I stopped by my local dealer and obtained an exploded view with a part number. One google search using that and look what I found...

Rear HVAC Actuator - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

Ring any bells?

 

[RayVoy]

I had an extend, the complete rear HVAC is mounted in the truck side panel behind the right rear side door. It uses ceiling vents and one big floor vent that is part of the panel covering the HVAC unit. To the best of my knowledge, the extended trucks do not use the vents that are part of the centre console.
The ducts for the console vents can only go forward, only to the dash, therefore, these ducts are part of the rear seat ventilation for the short trucks.

 

[cmatt]

Thanks for the input. I realize that it's not directly connected to the rear HVAC unit. However, I have confirmed that there is a functioning actuator/vent assembly in there.

 

[RayVoy]

That may be so, if there is one, it would be connected to the front blower motor. I guess a quick test would be to change the front blower speed and see if the air changes at those vents. It is probably there so that there would be some air movement in the rear if the rear fan is off.

The short trucks that had a second blower motor for the rear seat also have a couple of console vents above the radio/HVAC controls, our trucks only have a dummy plate.

 

[cmatt]

Good point. I'll test it and report back.

 

[cmatt]

Tested the front HVAC with different modes/speeds. No change from the lower rear console vents, barely any air movement.

Is there anything out there that states what situations the console actuator would move the baffle?

 

[The_Roadie]

The shop manual for 2004 says it should be slaved to the rear aux actuator, but that isn't consistent with Ray's post that the console has no upper vents on the EXT. If there's only floor vents, I see no reason to have an actuator at all. I'm stumped.

 

[RayVoy]

no upper vents on the EXT. If there's only floor vents, I see no reason to have an actuator at all. I'm stumped.

I agree Bill, I think there is an actuated only when the console is used with the short trucks that have rear air. The actuator would change the air flow from the floor to the top of the console.
I think the console is used in both trucks, just check the pic in the 1st post, connector #4 is used with the long trucks, and connector #5 would be in the console when used in the short trucks.
I suspect air moving under the dash is being felt at the un-used vents at the rear of the console.
Removing the interior box of the console should help, there would be ducts to the vents if they are being used.

 

[neelskit]

The floor vent actuator on the console allows air flow when the rear system is set to floor or blend. The air speed and temp actually comes from the front passenger system through a duct that runs under the console. If you set the rear system to floor, (with either the front or rear control) the actuator opens this floor vent. If the the rear system is set to vent (roof) or off, the actuator closes this floor vent. The rest of the vents in the rear EXT system (roof and rear floor by the third row seats) are all supplied by the rear system located in the rear passenger cargo area. The rear fan and temp setting will have NO affect on the console floor vent since the vent is supplied by the front passenger duct work.

An easy test is to set the rear system to floor and turn the fan for the front system to hi. You should have substantial air flow from the console floor vents. Then turn the rear system to either vent or off and the air flow should stop.

 

[RayVoy]

The floor vent actuator on the console allows air flow when the rear system is set to floor or blend.

The rear fan and temp setting will have NO affect on the console floor vent since the vent is supplied by the front passenger duct work.

I'm sorry, but I find these statements to be conflicting.

The air speed and temp actually comes from the front passenger system through a duct that runs under the console.

Yep, we agree on this as far as the short trucks are concerned. In my post above, I suggested the duct might not exist in the long trucks and that pulling the inside box out of the console might answer that question.

An easy test is to set the rear system to floor and turn the fan for the front system to hi. You should have substantial air flow from the console floor vents. Then turn the rear system to either vent or off and the air flow should stop.

I agree, a good test if the rear controls are set for the driver to control, when the control is passed to the rear passengers, the flow should stop. The OP has reported there appears to be no difference in air flow when the controls are on front and floor.

 

[neelskit]

This is how the rear system in my EXT operates...

If the front control is set to "0," air flow is restricted on the console floor vents.

If the front control is set to "1, 2, or 3" and...
A) the front system is set to floor or blend, air flow is allowed through the console floor vents.
B) the front system is set to vent, air flow is restricted on the console floor vents.

If the front control is set to "R" and...
A) the rear system is set to floor or blend, air flow is allowed through the console floor vents.
B) the rear system is set to vent or OFF, air flow is restricted on the console floor vents.

When air flow is allowed through the console floor vents, the air temperature and volume will be the same as the front passenger regardless of what the rear temperature and fan speed are set to, as the console floor vents are fed from a duct attached to the front passenger plenum.

There is NO duct work that runs from the rear plenum to the 2nd row floor- this is why the system operates in this manner.