[hrich]

Ok i just installed a new a/c control unit in the dash of my 99 wrangler because the old one quit controlling the fan speed. So i just got a new one. I got it put all back together and now it only blows air out of the defrost. It worked fine on the old one.If anybody can help me it would be great. thanks

[Ross]

Originally Posted by hrich

Ok i just installed a new a/c control unit in the dash of my 99 wrangler because the old one quit controlling the fan speed. So i just got a new one. I got it put all back together and now it only blows air out of the defrost. It worked fine on the old one.If anybody can help me it would be great. thanks

When the blower motor ages it melts the wires in the switches. You fan speed and the the controller that controls where the air goes can melt. The later switch is controlled by electric switch and vacuum. If it has melted it could be leaking and therefore unable to control the direction of air flow. There can be other reason too, this is just one I encountered.

[freeskier93]

Could have saved you a couple hundred bucks and told you to just replace the switch and not the whole HVAC controls.

I guarantee you have a vacuum leak somewhere or something is not connected. At the firewall where the heater/ac hoses enter the cab, there is another smaller tube for vacuum. Trace that to the intake manifold and vacuum reservoir in the fender. Check for cracks and make sure it's connected to the intake manifold.

Then under the drivers side dash, there are three metal canisters on the heater box, make sure the vacuum lines are connected. Finally check everything behind the HVAC controls.

[hrich]

Well the new unit only cost me 86 bucks brand new. And as of the problem with the a/c it must of just needed some run time to get vaccum back because it actually started working great.