Cadillac Repair: 1992 cadillac dash lights, cadillac fleetwood, fuel mileage

Question
92 cadillac fleetwood no dashlites heater control display fuel mileage display quite working i replaced the bcm it smelled burnt it worked for 2 min and quite again. the heater motor also wont run  

Answer
Most likely a short in one of the numerous solenoids that operate various components within the vehicle and or a shorted instrument panel.

This is going to require expert extensive diagnostic work to find the cause. See your dealer or major service center.