Why does 1990 Chev Cavalier keep blowing fuse for heater blower motor?

1. Faulty Blower Motor: Inspect the blower motor for any signs of damage, such as a seized bearing or burnt-out windings. A faulty motor will draw excessive current, causing the fuse to blow.
2. Defective Blower Motor Resistor: The blower motor resistor controls the fan speed. A faulty resistor can malfunction, allowing too much current to flow through the circuit and blowing the fuse.
3. Short Circuit in Wiring: Check the wiring between the fuse box, blower motor, and switch for any signs of damage or exposed wires. Short circuits can draw excess current and blow the fuse.
4. Faulty HVAC Control Module: In some cases, a malfunctioning HVAC control module (if equipped) can send wrong signals, leading to excessive current draw and blown fuses.
5. Overloaded Circuit: Check if any additional accessories or devices are connected to the same fuse circuit as the blower motor. Excess power consumption can cause the fuse to blow.

Before performing any electrical work, always disconnect the battery to avoid accidental electrical shock. It's recommended to have a qualified automotive technician diagnose and rectify the issue if the problem persists or if you're uncomfortable troubleshooting electrical systems.