The fact that one is warming up even when the truck isn't on suggests a problem. Here are some possibilities:
* Parasitic Drain: A short circuit or faulty component in the rear HVAC system could be drawing power from the battery even when the vehicle is off. This will drain your battery over time.
* Residual Heat: While less likely to be the sole cause of the warmth, the heater core might retain some heat for a while after the vehicle has been run. However, significant heat indicates a problem.
* Faulty Relay or Switch: A malfunctioning relay or switch related to the rear heater could be keeping power supplied to the heater core even when the system is off.
What you should do:
1. Check your battery: See if your battery is draining faster than usual. This is a strong indicator of a parasitic drain.
2. Disconnect the battery: Disconnect the negative terminal of your battery to eliminate power to the system. If the box stops warming up, you have confirmed a parasitic drain.
3. Professional Inspection: Take your Jeep Commander to a qualified mechanic or auto electrician. They have the tools and expertise to diagnose the exact problem and repair the faulty component. Ignoring this could lead to a dead battery and more significant damage.
Don't attempt to fix this yourself unless you have experience working with automotive electrical systems. Incorrectly working on the electrical system can be dangerous.
