No one likes sweating in a hot car in the middle of summer, and it’s especially infuriating when there is a perfectly good air conditioning system on board that doesn’t exactly function like it should. The 1999-2007 Silverado/Sierra/Tahoe, and other similar GM trucks all suffer from several maladies that eventually affect the HVAC system, and this is how to fix a couple of the more prevalent ones.
When we purchased this 2005 Silverado crew cab, we knew the good deal moneywise meant a little work on our part to fix things here and there, but that’s ok, because who doesn’t like fun weekend projects. In all reality, many of these issues can happen even on newer trucks with far less mileage than our subject vehicle. Luckily it doesn’t cost and arm and a leg to fix them.
There are a number of symptoms of a problematic HVAC system, and while we won’t be covering the under-hood issues that can arise, what we found when researching our particular set of issues was that they were very common among these models of trucks. And most are remedied with replacement parts inside the cabin.
Our first issue was that the #4 speed on the control dial would seldom work. One might immediately think it is the dial or HVAC control panel, but it is far more likely to be a bad blower motor resistor. Sometimes it’s one speed and sometimes it might be multiple speeds that you have lost. One other thing to note about the blower motor resistor is that the harness has also been known to fail, so if you think you have a bad resistor, go ahead and inspect the harness before you purchase your new one, as it can be had with and without the harness.
Problem #2 was that the driver’s side vents would occasionally start blowing hot air—yes, only the driver’s side while the passenger side would remain ice cold. This issue stems from a failing blend door actuator. Depending on your vehicle there are at least two, and possibly three of them. It depends on where the air is (or is not) blowing from as to what actuator it is. From our research, the one at the bottom of the dash right by the trans tunnel is the most common and the source of our issue.
Some people may find that they have other issues altogether or similar ones to these. The good thing is there are plenty of online resources for these trucks, and YouTube is also a good source with installation videos available as well. Check out the captions to see how we are now keeping our Silverado’s cabin nice and cool.