2006 Holden Rodeo heater not working. Wont blow warm air

SOURCE: 97 rodeo heater fan wont blow i checked fuses

I would check your blower motor. That sounds like the problem.

SOURCE: heater wont blow warm/hot air

check your radiator coolant, thats what I did and it blows warm again

SOURCE: My heater in my dodge caravan does not blow hot

First of all make sure your anti-freeze is at specification level's as well as make sure With the engine cold start the vehicle remove the radiator cap and make sure you see the flow of anti-freeze while keeping your hands as well as your clothing away from moving parts feel both hoses going into your heater core if the one on top of hot one on the bottom is cold then you have a Clogged heater core in which case you will need to flush the system . a simple garden hose will do the trick simply remove Both hoses to the heater core with the hose at the bottom line apply the garden hose until liquid comes out at the top of the other hose will probably see a lot of gunk. Also ensure that the vacuum line to the round ball under the hood is connected and not dry rotted.this will cause a vacuum leak to not allow the switch to fully engage from cold to hot. I hope this helps you.

SOURCE: When driving, heater blows warm air. When idling, cold air.

It sounds to me like you have a plugged heater core, or one that is beginning to plug. With the engine running, carefully feel the two hoses that lead from the engine into the heater core in the firewall. If one of those hoses is colder than the other one then you heater core needs to be replaced. This involves removing a bunch of stuff under the dash. Sometimes it's pretty easy and sometimes not. Start by removing the glove box and you should be able to see the plastic housing for the heater core.

SOURCE: The heater in my 2006 Dodge Grand Caravan only

Three possibilities:

Cooling system low on coolant. This causes erratic heater operation. Fill it and troubleshoot the leak.

Heater core plugged. Find this by bringing the engine up to operating temperature. With the blower on high, feel the heater hoses going into the firewall. They should both be pretty hot. One should be a little cooler - within 20 degrees of the other. If the core is plugged, the cooler one will be alot cooler than the hot one. Please note that restricted / poor coolant flow can mimick a bad heater core but is a rarity.

Blend door system malfunctioning. This can cause warm air when airflow is low but not provide warm air with higher airflow rates.