The temp controls on my 98 civic won't go to extreme hot, or cold. When put on cold, it blows cold. When I turn on the heat, it still blows cold... Any suggestions?

 

The linkage must be jammed if you're saying you can't physically turn the dial all the way. If the dial does turn all the way, check that the water valve under the hood (behind the engine, on the firewall) opens and closes when you turn it. Does the temperature gauge come up to normal when you drive? If it stays at cold that could mean the engine thermostat is stuck open, and that way you will get little heat. Also make sure the radiator is full. Don't just look in the coolant jug, with the engine cold remove the radiator cap and it should be completely full.