I just replaced my alternator amd belts this past summer was having no problems and now when I have the heat running sometimes my enguine squeaks. Mostly when the defrost is on. It aslo will happen if I have the lights, radio, and heat or defrost on. My lights dim when the squealing starts and sometimes my radio shuts off then back on. To stop the squealing I have to turn heat off and accelerate and it stops but as soon as I hit the breaks it starts again if I dont turn my heat off before I stop. It squeals when started sometimes too. Scince I replaced the belts and alternator would it be a new battery I need?