When I turn on the heater/ac the red warning light by the battery meter flickers on and the voltage goes down. If I turn off the heater/ac it goes back up to the middle normal position. Also if I come to a stop and my turn signal is on the light also flickers. If I am driving it seems to be fine even if I roll up the windows it seems to be drawing a lot of battery power. Any suggestions as to what it might be? Someone said fuses maybe. Help.