I just replaced my ac control unit and the resistor(blower motor). now my ac is only coming out of the defrost vents. is there a way to fix this w/o a computer or do i need a computer to fix it?any help appreciated

 

Hi I got a few things for you to check. The duct work in your truck uses diverter doors that are vacuum operated. You either have a cracked or loose vacuum line or you have a little critter nest stopping the little diverter door from actuating. Hope this helps.

 

I would start by posting more info about your vehicle...if your driving a 1980 p\u then we may start having your chack the vacuum lines....if your in an 09 then its a totally different ball game