Car has no heat with climate control temp sent at 90 cars runs great no heat blows cold air.

The core is clogged or has air in it. If you are not overheating, I'd suspect clogged. Flush it.

Car has no heat with climate control temp sent at 90 cars runs great no heat blows cold air.

Remove the glove box @ 5 screws. You'll find an electric motor with a rod attached to it close to the back of the firewall. This part controls a door that allows hot from the heater core or cold air from the evaporator to enter the car.

Check and see if the electric motor is moving the rod and door it is attached to by adjusting the temperature up and down on the climatic control panel.

If the rod is all the way to the left it is in the cold position and all the way to the right is hot. You can also snap the rod out of the electric motor to operate the temperature control door manually for verification.

If the motor is not moving the rod it could be a bad electric motor (check for power to the motor first) or one of the controllers to the climatic control system.

Be careful with the air bag system. You will want to pull the aur bag fuse

Nope not overheating she's running great so ill flush it ranger

Doesn't that car have a vacuum controlled coolant valve for the heater?

Not familiar with the Deville that year. I have a Fleetwood.

I wouldn't swear to it, but I don't think so.

Let me guess it's never been replaced. Try flushing it first but it sounds like it's time to replace it.

ok ill try that and ill let u know what happens

ok ill try that and ill let u know what happens

Flush and BACK flush. Watch the heater core for a while. Mine developed leaks from the gaskets. Had to replace with all aluminum aftermarket one. The original heater core had two plastic side tanks.