HVAC Controller issue,

[Tyger255]

Hello, Just bought a 2003 Suburban for the wife and family to use on vacations. Found one that runs and drives great but does have a few gremlins hiding inside.

2003 Suburban. Having HVAC controller issue. The fan speed control works ok. the temp selector does not change air temp. only blowing cool air. unable to change air flow from floor to dash to defrost vents. only blows from dash vent. Also the back lights do not light up when headlights are on.

The rear controller on the roof seems to work ok for the bank vents. I can change from cool to heat and change the fan speeds. but those are on a different control panel.

I've googled for a few days on this issue, I've tried pulling the HVAC fuse to reset reset the system a few times with no luck. I pulled and tested all the fuses that listed HVAC or any type of control on them, didnt find anything out of place. I've pulled the controller from the dash, The plugs and wires look ok, dont see any issues with the pins or rear of the controller.


I dont think this is related but the Radio was not getting a switched 12v power to turn on with the key,
thank you for any help. Radio fuse seem to be ok. I ran a jumper from a switched 12v power wire so now the radio works. Looks like the previous owner had a system installed. I found some boot leg wiring for it. Pulled all that junk out and think I've got most of that fixed. Dont think its related to the HVAC issue but thought I would list it in case someone thought it is.

It almost seems that the plug on the right side of the controller, that would control them and vents isnt working or doesnt have power. I'm planing to get a Haynes book on the way home tomorrow so I can trace the wiring for the plug and test with a meter. Hoping some one here might be able to point me in the right direction on where to start looking.

I would be grateful for any help.

 

[Scottydoggs]

give this a shot, its a hvac reset. needs to have the auto button.

theres a load of actuators that control the temp and direction, you need to take the dash cover off and cut a duct out if you need to replace 2 of them. they are in a crap place. theres more vids that cover that job.

no clue on the radio. i hate electrical stuff lol

 

[rabidcoyote666]

will be trying this fix in the morning....thankx.......

 

[Tyger255]

give this a shot, its a hvac reset. needs to have the auto button.

theres a load of actuators that control the temp and direction, you need to take the dash cover off and cut a duct out if you need to replace 2 of them. they are in a crap place. theres more vids that cover that job.

no clue on the radio. i hate electrical stuff lol

thanks for the quick reply.

I tried a reset similar to this but my controller has the 2 sides in the middle and not the digital display. I will try it again following these instructions and see if it changes anything. I hate working on electrical on vehicles also because its such a pain to get to all the wiring behind the dash. But if this is going to be our vacation vehicle I'll have to track down this issue. I dont want to take it to the shop to fix it less then a week after buying it

 

[Scottydoggs]

heres the one with the dash off, he shows all 4 of them. getting the dash cover off looks easier then you'd think really. just clips and a few screws hold everything on.

 

[Tyger255]

heres the one with the dash off, he shows all 4 of them. getting the dash cover off looks easier then you'd think really. just clips and a few screws hold everything on.

this video is great, with him showing all the actuators and the wiring I'll be able to track and test everything coming from the rear plug on the controler to the actuators to find my problems.

great help!

 

[Tyger255]

After using this video, tore down the dash, fixed several wiring issues, and found a few of the blend actuators that are starting to fail. Going to order and replace all 4 of them and that should have everything fixed up. After all thats working correctly I'll move to the A/C compressor. Think its low on Freon,

Thanks a ton for pointing me into the right direction. And FYI, the top part of the dash is just as easy as he explains. looks like a tuff job but I had everything apart and tracing wires in about 30 mins

 

[Tyger255]

Wanted to update this post.

With having vacation last week with my daughter out on spring brake I was able to replace the blend doors for heat/cool on drivers side (works now) and for the defrost/dash vent/floor vents. This one Im still having an issue with. I have pulled the HVAC fuse under the hood and let it run threw its calibration cycle, doing this it cycles the vents threw defrost, dash vent, and floor vents. After this, I am unable to change it using the controls on the dash. It ends its cycle at the dash vents and stays there.

Not sure what else to check from here. I've went back over the videos listed here and googled around a bit more but no luck.

I did fill the A/C system with Freon, it worked great for a few days then leaked back down. I'll get on that next time I have a few days to get under the hood and track that down.

thanks again for all the help