Diagnosis
The heating element is failing or the thermal cutoff fuse has blown. A solid blue light with insufficient heat points to a heater circuit problem.
How to Fix It
First, test a different wall outlet. Ensure you're not using an extension cord. Let the unit sit powered on (blue light) for a full 10 minutes. Feel the barrel carefully—it should be very hot. If it's only warm, the heater is underperforming.
If That Didn't Work
The internal thermal fuse is a one-time safety device. If it trips due to an overload or overheating, it opens the circuit permanently. This requires a professional repair to replace the fuse, which is often not cost-effective.
Heads Up
A unit that powers on but doesn't heat is still consuming electricity. Unplug it when not in use to prevent any potential short-circuit risk in the faulty heater assembly.