I've been having issues with my drivers side getting hot while the passengers side stays cold, after searching I found out that the C5's also had this issue and found a pretty cool write up for them. I went ahead and did it for the tahoe and tooks pics and thought I'd post them up for those that have a Chevy Tahoe/Suburban/Silverado that are having an issue where the Drivers Side AC cycles from cold back to hot...thanks to those that posted the orignal write up for the C5 on CF.
Ok so i've been having this issue for the past year...at first it started out once every few months but has now progressed to at least once or twice a day. Turning the truck off and then back on used to work but now when I do it, it'll go back to hot after starting the truck for a few seconds.
I've read on here and several other places and found some good write-ups on what the problem is and I felt my issue was my Heater Blend Door Actuator. The actuator uses a scrubber brush attached to a gear to monitor the position of the door when it opens and closes, i have heard that the contacts on the inside can get dirty causing faulty readings, the main gear can crack, the teeth can break off, or the unit go bad alltogether, so I decided to check mine out and HOPE it was something as simple as a broken tooth or gear...So I followed the steps below and so far so good worked for me.
You first have to remove the cover which is held in place by 4 7mm bolts. After you remove it, this is what it looks like...here is a pic of the actuator...its on the passenger side, just above the transmission tunnel:
There are two 5.5mm bolts holding the actuator on...remove the two bolts then pull it down to release it. here is what the actuator looks like removed:
Some people have screws holding their case together, mine had snaps holding the acutator together...just get a small flat blade screwdriver and pry the tabs up to release them:
Here is what the acutator looks like with the cover removed:
What I did from this point was mark the gear on top in relation to the black shaft or main gear that turns the door:
Next mark the main gear in relation to the body of the actuator:
Remove the top gear along with the black gear. Here is what the bottom of the black gear looks like, you'll see the two "brushes" or contacts that let the actuator know what position the doors are in:
On the circuit board just under where the main gear is you'll see the contacts that touch the brushes (the two curved contact paths):
On my actuator, it was full of hard grease and dirt. I used some Q-tips to remove all the grease from the contacts then some alcohol to make sure there wasnt any grease left on them. After you clean it up, put the black gear back on, making sure to line up the mark you made with the one on the case, then put the top/white gear on and make sure you line that one up also...then snap the case back together and reinstall.
From this point you have to remove power from the system, I read about disconnecting the battery and removing the airbag fuse and touching both battery cables together but didnt feel too comfortable doing that so the write-up I was reading said, with the truck off, turn the AC off, remove the AC fuse for one minute, then turn the truck back on and dont touch anything for 4 minutes so that the actuator can relearn the stops. There are two fuses for the AC in the cabin on the left side of the dash, one is a 30amp fuse and the other a 10amp. You also have a 10amp one under the hood...i went ahead and removed all three for one minute, then put them back in, turned on the truck and let it run for 4 minutes. As soon as you turn on the truck, if you get down by the actuator you can hear it cycle from one side back to the other side. I've been driving the truck all day and havent had any issues with it at all...once again before, it was happening every time you turned on the AC. So i'm hoping for me my contacts were just dirty and it had to relearn the stops. if this for some reason doesnt work, they also recommend you reindex the actuator by removing the gear and turning it two teeth counter-clockwise. If that doesnt work turn it two teeth clockwise (past where it was originally). If that still doesnt work, then replace the actuator. I called the dealership and it was like $267, but found it online somewhere else for half that. I ordered it anyway just in case this doesnt work, plus it wouldnt hurt to have a spare one just in case...hope that helps!!!