88 seville ????

i'm looking at getting a 1988 cadillac seville,but need some input please on a couple of problems (1.the dash wont light up ,well no gas gauge ,no speedometer,and whatever else that goes in that area,what should i look for or at?,(2.the heater is not getting warm ,have it @90 deg on the temp on the heater,could it be the thermostat or heater core? any thoughts?it runs and drives, great and the temp on the same area as the temp control reads 225-235 degrees,any help before i spend the money on this car.$400
thanks keith

I would look at the bcm as that controls the gauges. no heat could be a few things. Thermostat for one, or a bad mode valve. would need to chack operation of them.

If you can access the diagnostic mode, you might find a code dealing with the display problem. I had a '87 Seville with this symptom , and it turned out to be the central power supply module.

thanks guys