What do you do when the heat in a 1996 Pontiac Bonneville stops working and the interior and exterior digital temperature gauge on the dash is flashing?

Answer 1

If you have the Automatic Climate Controls (where you have switches to control the temperature, and fan settings, instead of knob's), and the temperature reading is flashing, it means there is something wrong with the Climate Control system. As for the heat, does the engine itself warm up? A common problem on the 90's Bonneville's is the "door" inside the dash that controls whether the vents throw out hot, or cold air, sometimes jams, or breaks. This would make your temperature gauge flash, and could also be why you have no heat. If I were you, the first thing I would do is make sure the engine is heating up. Don't go touching things in the engine bay that may burn you, but make sure the engine is heating up, and if it is, I would get that "door" under the dash looked at.