21 replies to this topic

[Superman TNT]

Great, just when I deside to sell my old truck along comes a problem. I live way up north, Vermont. It is still cold in the mornings here and requires heat. I have a 2001 Silverado 1500 Z71, 4x4 w/ 5.3l V8. This morning I turned the temperature control over to the hot side . . . no problem the heater started putting out the heat. This afternoon I ran over to the PO and when I turned the heat down, back to cold, nothing changed. It is suck on HOT. The fan works fine. The directional switch works fine. The only problem seems to be the temp setting. I noticed that when I turned the truck off and back on 7 minutes later the temp reset back to cold (where I had left it).

I tried repeating this and sure enough if I turn it to hot it will go that way but it won't go back to cold. I can turn the control just fine but the mechanics down below don't switch. I tried turning it off again and sure enough it reset back to cold again hen I turned it back on.

Anyone ever had this happen? I have no clue what to even look at for this. Is there a cable underneath the dash that could be hanging up and somehow gets loose when I shut it off?

Ideas anyone?

Thanks,

[dbunn]

I almost dont want to post this because it really doesnt answer the question. But - I had a Pontiac Grand Prix that was only a year old with the fancy dual zone climate control. Several times that would happen. I tried several things to get it to reset or unstick. Never could find a rhyme or reason. However, when it occured (whether it was doing A/C or heat) I noticed that the area under the dash was extremely hot. I would check the feel of it when it was working properly and it was never as hot. Of course the thing would act up when I was on a road trip or it was not convenient to take it in. I assumed that for whatever reason it was getting freaking hot and was not allowing some electrical motor or something to work properly.

Sorry if all I did here was waist bandwidth.

Good luck.

Dan

[BigDaddyHD]

Your temperature control actuator is bad. It's a little motor that moves the temp door. They are about $70 at the dealer. To change it you need to remove the knee trim panel on the passenger side (3 screws, 7mm socket). The actuator is in the center above the transmission hump. It has one harness plugged into it and 2 screws (5.5 mm). Take the screws out and it should drop straight down. Align the actuator with the lever on the door and put the screws in. Plug the harness back in. Turn your temp control to cold and remove the HVAC 1 fuse. Should be in the fuse panel on the drivers side of the dash. Turn your key to run and leave it on for at least 1 minute. Turn your key back off and put the fuse back in.
P.S. The trim panel is a PITA to get off, so while you have it off check to see if you have the cabin air filters and change them while you are under there.
Big Daddy
Also there is an article in the Tech Corner on changing the cabin air filters.
GM# 52474810

Edited by BigDaddyHD, 29 April 2005 - 07:49 PM.

[Superman TNT]

Thanks to both of you for the replies! I will try the repair this weekend. That was a lot of detailed info for someone new to the forum. You sound like you have a lot of experience. Anyway, thanks again.

[MyZ71Truck]

I have a 2000 Chevy Z71 that had the same problem. BigDaddyHD's post was exactly correct. I was able to pull a temperature control accuator from a late model Chevy Blazer at my friends junk yard and it worked perfectly.

Thanks BigDaddyHD for the detailed resolution and instructions!

[unit731]

What trucks have a cabin filter?

[JessBuice]

I have a 1500 sierra, 1991. The heat and AC digital lights flash if I push the bar past the first indicator light. The console was replaced three times, twice it fixed the issue. Now with even a new console it flashes. The dealership says I need a new actuator? Any ideas on where to locate the actuator? How to replace it, or is some other issue?

Getting cold here, haven't had heat for three years. Appreciate your assistance.

Jess

[BigDaddyHD]

The 88-98 trucks use a similar setup on the actuator. But I'm not sure of it's specific location.

[Bi11ydean]

I have a 1500 sierra, 1991. The heat and AC digital lights flash if I push the bar past the first indicator light. The console was replaced three times, twice it fixed the issue. Now with even a new console it flashes. The dealership says I need a new actuator? Any ideas on where to locate the actuator? How to replace it, or is some other issue?

Getting cold here, haven't had heat for three years. Appreciate your assistance.

Jess

[Bi11ydean]

Jess, I have the same problem with my 91 chevy. Did replacing the actuator do the trick?

[M. Cueva]

Here is some info that might be helpful, also I am not sure which RPO codes are on your truck, but here you go:



Document ID# 1989063
2001 Chevrolet Chevy C Silverado - 2WD

Subject:Repeat HVAC Actuator Replacements - keywords door cool heat mode temperature #PIT4427 - (06/15/2007)

Models:2003-2007 HUMMER H2, SUT

1999-2007 Chevrolet Silverado Classic

1999 -2007 GMC Serria Classic

2002-2006 Cadillac Escalade, ESV, EXT

2000-2006 Chevrolet Avalanche, Suburban, Tahoe

2000-2006 GMC Yukon, Yukon Denali, Yukon XL, Yukon Denali XL

2002-2007 Chevrolet Trailblazer Models

2002-2007 GMC Envoy Models

2004-2007 Buick Rainier

2005-2007 Saab 9-7X

1998-2004 Chevrolet S/T Classic Blazer and S10 Pickup

1998-2004 GMC S/T Classic Jimmy and Sonoma

1998-2007 Oldsmobile Bravada

2003-2006 Chevrolet SSR

This PI Being Updated To Add Additional Model Years. Please Discard PI02080.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.


Condition/Concern:
A replacement HVAC actuators is inoperative or that has worked one time and quit. The HVAC control head learns the stopping points based on how far the HVAC DOOR travels. If the actuator reachs the mechanical stops on the back of the actuator it will be outside of the range that the HVAC control head can learn. If the actuator was not mounted to the HVAC case prior to plugging in its connector, the actuator will go out of range and be inoperative.


Recommendation/Instructions:
Always attach the HVAC actuator to the case before installing the electrical connector.

If an actuator is out of range it may be possible to bring it back into range by following the procedure below:

• Turn ON the ignition, with the engine OFF.
• Connect a 3 amp fused jumper wire between the actuator control circuit and the 5 volt reference circuit of the actuator connector.
• Remove the jumper wire and actuator connector when the actuator is at the center position.
• If the actuator doesn't move in step 2. Try installing the jumper wire from control circuit and the ground circuit of the actuator.
• With the actuator in the center position, install the actuator to the hvac case and secure the mounting screws and then connect the actuator connector.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.



GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

© Copyright General Motors Corporation. All Rights Reserved.

Document ID# 1989063
2001 Chevrolet Chevy C Silverado - 2WD















Document ID# 888399
2001 Chevrolet Chevy C Silverado - 2WD
Mode Actuator Replacement (W/D07)

Removal Procedure
Notice: In order to avoid actuator damage, DO NOT apply power to the actuator when it is not installed in the HVAC module.

• 
  
• Remove the floor air outlet duct extension (1) from the floor duct (2).
• Remove the center console. Refer to Console Replacement .
• Remove the screws from the center console duct.
• Remove the center console duct.
  
  
• Disconnect the electrical connection from the mode actuator (10).
  
  
• Remove the mode actuator mounting screws from the HVAC module.
• Remove the mode actuator as an assembly with the actuator cam.

Installation Procedure

• 
  
• Install the mode actuator as an assembly with the actuator cam.

  • Line up the heater/defroster valve lever with the mode actuator cam slot.

  • Line up the A/C valve lever with the mode actuator cam.

  Notice: Refer to Fastener Notice in Cautions and Notices.
  
• Install the mode actuator mounting screws to the HVAC module.Tighten
  Tighten the screws to 1.6 N·m (14 lb in).
  
  
  
  
• Connect the electrical connection at the mode actuator (10).
  
  
• Install the center console duct.
• Install the screws to the center console duct.Tighten
  Tighten the screws to 1.6 N·m (14 lb in).
  
• Install the center console. Refer to Console Replacement .
• Install the floor air outlet duct extension (1) to the floor air duct (2).

Document ID# 888399
2001 Chevrolet Chevy C Silverado - 2WD

[M. Cueva]

Second post because of the number of images:






















Document ID# 659211
2001 Chevrolet Chevy C Silverado - 2WD
Air Temperature Actuator Replacement

Removal Procedure

• Remove the instrument panel hush panel .
  
  
• Disconnect the electrical connector (8) from the air temperature actuator (9).
  
  
• Remove the air temperature actuator retaining screws.
  
  
• Remove the air temperature actuator.

Installation Procedure

• 
  
• Install the air temperature actuator.
  
  
  Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
  
• Install the air temperature actuator retaining screws.
  Tighten
  Tighten the screws to 1.6 N·m (14 lb in).
  
  
  
  
• Connect the electrical connector (8) to the air temperature actuator (9).
• Install the instrument panel hush panel.
• Calibrate the HVAC module actuators. Refer to Re-Calibrating Actuators in HVAC Systems - Automatic.

Document ID# 659211
2001 Chevrolet Chevy C Silverado - 2WD

[M. Cueva]

Third Post due to limitation of images:



























Document ID# 626318
2001 Chevrolet Chevy C Silverado - 2WD
Mode Actuator Replacement (W/O D07)

Removal Procedure

• 
  
• Remove the floor air outlet duct extension (1) from the floor duct (2).
  
  
• Disconnect the electrical connection at the mode actuator (10).
  
  
• Remove the mode actuator mounting screws from the HVAC module.
• Remove the mode actuator as an assembly with the actuator cam.

Installation Procedure

• 
  
• Install the mode actuator as an assembly with the actuator cam.

  - Line up the heater/defroster lever with the mode actuator cam slot.

  - Line up the A/C lever with the mode actuator cam.

  Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
  
• Install the mode actuator mounting screw to the HVAC module.
  Tighten
  Tighten the mode actuator mounting screw to 1.6 N·m (14 lb in).
  
  
  
  
• Connect the electrical connection at the mode actuator (10).
  
  
• Install the floor air outlet duct extension (1) to the floor air duct (2).
• Calibrate the HVAC module actuators. Refer to Re-Calibrating Actuators .

Document ID# 626318
2001 Chevrolet Chevy C Silverado - 2WD

[M. Cueva]

check the RPO Codes in the titles of each post to see if it applicable to your truck, sorry I didnt realize that the reply box also had a character limitation..........

[Denton1]

I just wanted to say that this worked perfect on my 2000 Silverado, was just about to take my truck into the dealer when I found this post. Changed out the actuator and works perfect now. Saying it is a PITA is an understatement getting the last screw out of the cover but wasn't to bad, also if you are changing the cabin filter at the same time, check and make certain you replace both of them. I didn't realize there were 2 until I went to got the replacement filter and it came with 2, you just have to fish the other filter out, due to it being slid up against the firewall, both can be removed from same opening. Tks again.