Driver Side Blowing Hot Air

ghellyer · October 19, 2008

During the summer the air on my ''05 Silverado 2500 HD started blowing incredibly hot air on the drivers side only...passenger side is still blowing cold. Chevy dealer replaced the main control ($550) and it did absolutely nothing to help.

Now that it''s getting cooler the stupid thing is blowing cool air instead of heat...again only on the drivers side..passenger side is fine.

I''m reading that some folks think it''s the actuator for the drivers side...could it also maybe the thermostat for the driver?

Can you tell where these items are located in the truck?

minibike132 · October 19, 2008

I would tend to doubt temperature sensors in this case unless there is a variation in temp from vents to floor. The reason I say this is there are four output temp sensors, Left Upper, Left Lower, Right Upper and Right Lower. All four sensors ground at the same point so you can probably rule out that branch of the circuit. If the left upper worked correctly but the left lower did not I would say start looking for a sensor issue, but if both are incorrect it isn't likely to be your problem. The actuator is probably your problem. Before you attack the PITA job of an actuator I would try a relearn. You will have to do this if you replace an actuator so I'll run that down for you.

Remove underhood fuses-HVAC/ECAS and BLWR, remove instrument panel fuse HVAC 1 and leave all three fuses out for a couple of minuites.
(key off) reinstall all fuses
get in the truck and turn the key on, DO NOT touch any of the hvac controlls.
leave key on for at least one minuite
turn the key off and exit the truck, close the door and wait another minuite.
lastly go for a drive and see what happens.

If this doesn't work for you it may need the actuator but without doing some electrical testing you can't be sure. The temp actuator for the left side is located in lower center portion of the airbox which is about dead center to the vehicle (think right in front of the console which you might need to remove to access it). A note of caution if you replace the actuator, do not plug the actuator in untill it is bolted in place. If you do and the key happens to be on it will do it's learn sweep and there will be nothing to stop it. In that case you kill a brand new part. It can be fixed but I couldn't begin to tell you how without being hands on. Make sure after you replace it if that is what you decide to perform the above learn cycle before trying the system out.

ghellyer · October 23, 2008

Thanks for your help....the learn procedure gave me hope but didn't fix the problem. I spent the afternoon taking out the console to eyeball the actuator. At that point I decided it was time to do battle with the dealer that charged me $5xx and didn't fix the problem. Long story short, it was the actuator on drivers side. And after a battle that was tooth and nail for a few moments (they wanted to charge me $169 for the part and $0 for the labor for that day)....they didn't charge me any additional $$ (keep in mind I already paid them $5xx) for the repair. For the 1st time in many months I have the correct temperature air coming out of my vents. This will make winter much easier to take.