Dodge nitro heat blowing cold air
if you are blowing cold air check the level of coolant, if full, check your thermostat, if that's fine then comes the most expensive the heater core. After that I'm out of thoughts.
It's more complicated than that. The 1st two possibilities you mention would likely have more symptoms ie: temp gauge reading too hot/cold. The heater core always fogs interior windows and spews a sweet moist taste in the cabin when that goes bad unless car manufacturers have somehow relocated the heater core to the engine side of the firewall which might make those symptoms change. I think it's more likely you would have a bad "blend door" actuator or maybe the electronic switch on the dash is malfunctioning. The switch is the cheapest fix, if it's the blend door, it's very time consuming for a mechanic to disassemble the dash enough to access the actuator. You can expect to pay a shop $900 in labor to do that repair. The part is relatively cheap.
After reading some more on forums and looking at my daughters '08 Nitro, I think there may be another possibility. The heater core can plug up. I removed the blend door motor from my daughters Nitro and manually moved the door. No heat yet, I plan to flush the heater core next. I'm reading that there can be some casting sand that may settle in there and perhaps corrosion from using the wrong anti-freeze or mixing different types (perhaps before we purchased the car). There's also talk of air getting stuck in the core, so it may be necessary to have a shop use a vacuum tool to flush the system properly.
By the way, that $900 labor estimate was WAY off. Apparently, the shop that told her that never even looked at the car. You have to be REAL careful where you take your car these days. I had the blend door actuator off in about 2 minutes!
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