We have just bought a 1996 Sun Voyager. It was a one owner and well taken care of. The ac comes on and blows cool air but has no force of air behind it. Does anyone know what it could be?

your fan motor might be getting ready to stop working,could be a loose electrical connection, you need to know everything that makes that circuit work, such as relays, fuses, etc., could just be some bad connection, there can be so many things that can cause this problem

gotta have a new switch its electronic

It sounds like your AC unit could be overheating or even damaged.

AC units have a sensor that will turn them off automatically to prevent damage from overheating. If there is an insufficient amount of air flow, the unit will heat up, and then eventually turn off.

When the car is moving, more air is forced over the unit, likely keeping it cool enough to run, however, when the car come to a stop, it loses that air flow, and quickly heats up. Thus, the AC would work while the vehicle is in motion, and overheat and stop when the car is stopped and idling.

However, the AC unit could be completely blown. The cold air while moving could be just a case of air being forced into the car. Think of a house fan, the fast the wind blows on you, the cooler it gets.... Thus, it could be an illusion that the AC is working when car is in motion, when it really isn't.

Hope this helps.

This happened to me and I tried everything to fix it before having to get a brand new main blower motor. As soon as I replaced it my air started to blow again and problem solved

2004 chevy Avalanches air conditioner blows hot air, can the actuator be forced to keep it blowing cold air instead of hot air all the time.

Check operation of heater coolant control valve, and it's associated remote control mechanism.
Check that both inlet and return heater hose is equally warm, as this indicates coolant flow through the heater core.
If no coolant flow:-
Check cooling system is correctly filled, taking care to bleed off any air locks from the system as necessary (with heater coolant valve open);
Check heater core is not blocked.

The AC filter of your car should be under the dashboard on the passenger side. While you have it opened it would be best to go right ahead and have other components clean to save you time.

Would have him check out side air temp sensor ,thermister and rerove control head and inspect for burned terminal.1st.

when the ac is on the computer is looking at pressure in the ac system to control the cooling fan operation if the pressure is increasing the cooling fan is commanded on now if the pressure switch is bad or if the ac system is low on refrigerant it is not building pressure and the cooling fans are not going to come on.

U have a AC refrigerant leak, that is why it worked for a week after the system was topped off, now it has leaked out again.