13 ls heat and ac control - TerrainForum.net: GMC Terrain Forum
LinkBack Thread Tools
post #1 of 2 (permalink) Old 06-22-2019, 01:41 PM Thread Starter
Jr. Member
fitter30's Avatar
Join Date: Feb 2013
Location: Peace Valley,.Missouri
Posts: 33
13 ls heat and ac control

Everything on the control panel lights up when button is touched, ac operates, defrost ac comes on but all dampers stopped working. All air blows out of face of dash. What to look for?
fitter30 is offline  
Sponsored Links
post #2 of 2 (permalink) Old 06-22-2019, 02:20 PM
Theta Guru
Join Date: Feb 2011
Posts: 3,286
Looking at how The Manuals describe my ‘11 - and this is assuming “Manual” HVAC system, you have at least three components here: the (1) Radio/HVAC Control panel which accepts the button presses to direct the air, the (2) HVAC Control Module, which gets the button presses from the Radio/HVAC Control to Control a (3) Mode Cam Actuator, located under the left-side dash below the steering wheel.

So now the question(s) are:

1.) Are the button presses at #1 getting to #2?

2.) Is #2 commanding #3?

3.) Is #3 getting the command, and if so - is it malfunctioning (or just dead)?

Without the aid of a professional scan tool to check #1, #2, or the network between them, I would just go straight to #3 by removing the small panel below the steering wheel and then removing the (3) screws holding the actuator in place - because that’s the most likely point of failure.

Can you hear any noise at this actuator when you press the buttons on the Radio/HVAC panel? I *twice* had something similar fail on my ‘97 Taurus when the same internal plastic gear cracked a tooth! In each case, you could hear it turning (and trying to move the air “blend” door), but when it reached the cracked tooth the door would fall down.

If you can’t hear anything, maybe you only have a blown fuse, but in 30+ years of maintaining all my vehicles - I’ve yet to replace a single fuse...
Attached Images
File Type: jpg 3A28D7E2-24E6-49D4-80D9-98DA3B0CCE52_1561224157882.jpg (397.9 KB, 3 views)

2011 Equinox 1LT (new Jan 2011): Summit White / 3.0 L V6 / FWD / Pioneer Stereo / 18" Wheels / 138.2k miles [05-NOV-2019]

2002 Impala 1LT (new Jun 2002): Summit White / 3.4 L V6 / FWD / Cassette-CD Combo /225.5k miles [05-NOV-2019]

Last edited by Colt Hero; 06-22-2019 at 05:04 PM.
Colt Hero is offline  

Quick Reply

Register Now

In order to be able to post messages on the TerrainForum.net: GMC Terrain Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome