my 2008 ram 1500 during heating position blows hot if your running A/C,but on normal mode just blows luke warm air thru the vents and floor area but blows hot on defrost mode

Hi, this is Bo, an auto expert on RepairPal's Car Genius team! Your 2008 Ram 1500’s heat situation sounds like a classic case of a misbehaving blend door actuator or an issue with the HVAC controls. The blend door is what regulates whether hot or cold air flows into the cabin, depending on the mode you select. If it’s not functioning correctly, it might be stuck or failing to adjust properly, explaining why the heat works differently depending on the mode (like defrost versus floor vents). The fact that the air gets hotter when using A/C suggests the system might be overcompensating by mixing less outside air. On "normal heat," it sounds like the blend door isn’t fully moving to the hot side, leaving you with lukewarm air. Defrost might bypass some of this, delivering more consistent heat. I’d start with a look at the blend door actuator, located behind the dashboard, and test it for proper operation. If that’s fine, the issue could lie in the HVAC control module or temperature sensors. If you need any further advice or want help finding a trusted RepairPal shop in your area, please feel free to call us at 877-913-1554.