This customer came in with the symptom that the heat wasn’t working on the passenger side of the cabin. She also mentioned she’d smelled coolant a few times in the past. The vehicle was equipped with an automatic climate control system, which allows for the driver and passenger to command different cabin temperatures.

Our technician verified the concern, and found that the electric motor was indeed attempting to move the air duct door, but the door didn’t seem to be responding. In order to see what was happening inside there, we had to remove the entire dash, thereby gaining access to the heating, ventilation, and air conditioning (HVAC) unit. Upon customer approval, we dug in.

After removing the dash assembly (see pic), and the HVAC assembly, and then disassembling the HVAC assembly, we found temperature door hinge broken (see pic). We also found a slightly leaking heater core, thus the coolant smell. Now, here’s the clincher: the leaking heater core had allowed coolant to drip into the temperature door hinge, thus rotting the plastic, ruining the hinge, and causing stress on the motor. The fix was a new heater core, a new hinge and door assembly (luckily this was sold separately!), and a new door motor. If the door motor wasn’t replaced and failed in the future, the customer would have to pay the seven hours of labor all over again to replace the door.

Full of surprises along the way, but a very interesting case!

Until next time,

Zach Edwards