Front fan blower won't stay on

 

The problem could be either electrical or mechanical.
To check electrical, all that needs to be checked is if power and ground are available at the time it is on then the problem is mechanical .If that is the problem we just replace the blower motor. Not that difficult a job, fast and easy.
If power and ground are not available at the motor when requested, we need to check back to determine just which it missing . This is one of the times it can safely be done with just a test light.