However, simply replacing the motor might not solve the *cause* of the squealing. The squealing for two years suggests there might be a bearing issue within the motor or perhaps even something rubbing against the blower wheel (like debris). Inspect the blower wheel and housing for anything that might be causing friction before installing the new motor.
You'll likely need to access the blower motor from under the dash. This usually involves removing some trim pieces and possibly the glove box. Consult a repair manual specific to your 1978 Ford F150 for detailed instructions. These manuals will show you where the motor is located, what needs to be removed to access it, and the proper procedure for installation. You can find these online (often through sites like eBay or Amazon) or at auto parts stores.
In short: Yes, it can be replaced, but also check for the root cause of the previous squealing to prevent a repeat failure.
