After 430,000 miles my 2005 has stopped heating? I remember back at 380,000 I heard a sound from the vents as the AC made adjustments back and forth. That I hear no longer. What is failing? iPhone ?
430000 is quite an accomplishment. Maybe the servo that controls the heating and cooling controls is the failed part. But before you start doing any major diagnostics, is there enough coolant in your radiator?
Take a glance in the repair manual as to whether there's an active test mode you can get into that exercises all the servos. My Gen 1 had such a mode that you could get into right from the controls with no extra tools. Gen 2 might also, I'm not sure. It will almost certainly have active tests available in Techstream, if you have that. Work the active tests, stick your head down there and watch what the servos do. If you were hearing servo noises 50,000 miles ago, it's worth a look. The Gen 2 servos are the same basic design as the Gen 1. -Chap
Turn the heater to max with warm engine. When the engine stops running (eventually) see if it now blows hot air? If it does then it’s the thermostat that’s faulty. If it doesn’t, test the temperature of heater core hoses. Here is the picture of how they are routed Coolant System Flush | Exclusively Hybrid You can test the temperature at any point of hose that you can get to (including before and after the heater water pump). If one hose is hot and one cold you have problem with coolant flow control valve, blocked heater core, or air in cooling system. If temperatures are about the same then the problem is with temperature control door. Problem with coolant flow control valve, or problem with temperature control door doesn’t necessary mean that that’s the faulty part it just means that the problem is related to them.
Honestly, if you've been hearing servo noises for 50,000 miles, check the servos. It's oversimplified to say "if no hot air blows, it's the thermostat." Doesn't matter what heat gets to the heater core if the air's being routed around it. -Chap
