System not heating and has a blown fuse for the main level. Found a short coming from the gas valve and has also shorted control board. The inducer motor is over amp as well. Lots of dust/dirt buildup inside the blower section. Inspected the heat exchanger and found major cracks . Inform the customer that this furnace is not safe to run at this time. Based on our findings today, it might be time to think about getting a brand new system.