Erratic HVAC operation can be a frustrating problem in 2011 Chevrolet Equinox and GMC Terrain vehicles. Symptoms may include intermittent changes in temperature, unexpected A/C shut-off, or unresponsive mode changes. Often, this issue won’t trigger any diagnostic trouble codes (DTCs), making it difficult to pinpoint the source. However, in some cases, the DTC B101e-4b, indicating a calibration error, may be present. This code might appear even after performing an HVAC actuator learn procedure.
A common cause of these intermittent HVAC problems is a poor connection within the actuator wire harness. If you’re experiencing issues with a specific mode, like temperature control not functioning correctly, standard diagnostic procedures outlined in the service information may lead you to a faulty actuator. However, for intermittent issues where no clear fault is found after inspecting connections at the HVAC module and actuators, the problem likely lies within the wiring.
The recommended solution is to replace the wire harness connecting the HVAC module to the actuators and the evaporator sensor. When installing the new harness, applying dielectric grease as outlined in Service Bulletin #09-06-03-004D is crucial to prevent fretting corrosion, which can lead to future connection problems. This bulletin addresses issues with fretting corrosion and provides guidance on proper grease application for electrical connections. This preventative measure helps ensure the long-term reliability of the HVAC system after the repair. Addressing the wiring issue and applying dielectric grease should resolve the intermittent HVAC problems and restore proper climate control functionality.
