unni
Active member
First, you have a leak in the vaccum system. May not be a breakage but most likely a hose pulled out. since you are mentioning that it is getting worse, the likelyhood points to a loose contact.
The default setting for almost all oem climate control system is to divert to defrost system as it is part of vehicle safety. The year of your vehicle suggests slightly older system. Reality check, you will have to trace it. Though it is not a mechanic only task. Can be done to a good part by you, depending on how flexible you are.
The vaccum from the engine intake manifold is connected to a vaccum reservoir which usually is a ball hanging on the hood itself. Looking for the ball or black cylindrical structure would be a good starting point in your trace. Vaccum lines are small black rubber lines or thin plastic lines. From the reservoir it usually goes to the cruise control system. But trick is, most manufactures tie the climate control lines with this as it comes in to the cabin. One line goes to the control valve/knob/switch for climate control . From there several lines are distributed to small climate control routing doors which are controlled by vaccum control units. This is tricky part to reach to. Since your defrost is getting air, this is where your problem lies too. 'Unfortunately'.
To start with, there are rubber hoses that goes into the cabin (volvos) or into a bulky unit attached to the firewall under the hood. 4 lines goes there. 2 heater hoses and 2 a/c hoses. This is the condensor and heater coil location. Air comes into this unit from outside usually and a fan blows it inside into various hoses to various locations in your cabin. 2-4 vaccum controls that looks like circular disks shaped caps on one side which had a hose attached and other side has a diagphram that actuates a door. Accordingly they select ac/heater, front or foot and in between. Good Luck. Ping back with some picture under the hood and under the steering wheel and passenger side.
