If little to no resistance is felt while operating the temperature control lever, what is the likely issue?

When little to no resistance is felt while operating the temperature control lever, it often indicates that the control cables have slipped loose. These cables are essential for physically connecting the lever to the components that adjust the temperature within the system. When they are properly connected, you should feel resistance as the lever moves these components. If the cables have become detached or have slipped from their mounting points, the lever will move freely without affecting the actual mechanism, leading to the sensation of no resistance. This issue disrupts the expected response of the temperature control system, making it difficult to regulate the cabin temperature effectively.

The other issues would present different symptoms. A broken lever would typically mean that the entire mechanism would be inoperative, while a faulty temperature gauge might provide erroneous readings but would not directly affect the lever’s resistance. A clogged heater core would lead to inadequate heating but would not usually impact the operation of the lever itself.