HOT HOT HEAT
| 2003 Chevrolet Silverado Hot Hot Heat Z
Question: I have a 2003 Silverado pickup that I bought almost new. It was a demo. Just after it was out of warranty, it started having an intermittent problem: On start-up or while driving down the road, the heat will work only on the driver's side. I can feel cold air coming from the passenger outlets, and nothing I do will make it stop until I shut the truck off. Then it's fine and it might not happen again for weeks. It's equipped with the dual automatic climate control system. A coworker with a 2004 truck equipped with the dual climate control system took his truck to a local Chevy dealer that replaced a control and actuator and charged him $1070. I'm a little concerned about spending this kind of money, because I can get it working again by shutting off the engine. But I'm afraid that one day it'll get permanently stuck in heat mode on a 90-degree day.
Answer: There's a good chance your intermittent problem is going to become a hard-core failure-and those usually happen at the most inopportune times. You're better off getting it fixed now. A Chevy service department is the best place to go for this type of repair, because the techs know the system better than anybody. So the chances of having an intermittent condition corrected the first time around are much greater. Going by your description, the problem may be the driver-side Air Temperature Actuator, an electric motor that positions the blend door to direct air through the heater core (hot), evaporator (cold), or a little of both. It looks like the replacement of the left actuator is no big deal, but the right side requires almost complete removal of the dash. You have to be sure before replacing anything. The dealership tech can scan the HVAC system for trouble codes that may lead him in the right direction, followed by additional component testing to confirm the fault. There's also a technical service bulletin that should be reviewed as part of the diagnostics. TSB #04-01-38-008 involves the HVAC actuator harness contacting a sharp edge on the instrument panel support brace. Wires in relative circuits are then shorted to ground, which can cause symptoms similar to what you're dealing with.
If you have a technical question regarding your pickup, SUV, or van, feel free to contact Alex, a master technician with the National Institute for Automotive Service Excellence. Send a letter to him in care of Truck Trend Garage, 831 S. Douglas Street, El Segundo, CA 90245, or e-mail us at trucktrend@sourceinterlink.com. Please include the VIN with your question. Due to the volume of questions received every month, we cannot guarantee that everyone's question will be personally answered or will appear in the magazine.
Can't wait for help with a problem you're having with your Truck or SUV? Ask the expert we trust here at Truck Trend Garage -- visit Alex Steele at www.RealWorldAutomotive.com.
