heat valve installed but still no heat....i tried posting about this problem previously but got no response. have changed the mono heat valve in my 88 sel but still have no heat. when put on defrost will blow hot air towards windshield but cold out side vents...freezing in ks last couple of weeks. am i missing something?

Is your car getting warm enough to produce heat? Could be your thermostat is stuck open.
What temperature does the dash indicate?

the thermostat has been replaced already and the temperature gauge indicates that the car is operating in normal temp ranges...marley

When the heater does blow hot air (towards the windshield) but not through any of the other ducts, I think one of your valves inside the heater housing is not controlled any more (due to a vacuum leak or broken vacuum pod).
A valve has to be opened inside the heater housing to let the incoming air flow through the heat exchanger so it gets warmed up.
My guess is that this valve stays closed and the incoming air is being led straight into the interior...

greetingz,

this would be a different vacuum system than the one that controls the doorlocks ect....all of the vacuum controlled equipment appears to be working fine. how do i go about rectifying this problem or is it something that i can't do by myself???? thanks for the reply....mr. marley

The two vacuum systems you mentioned are separate and not related. Replacing the heater solenoid valve/mono valve is not enough to correct your problem. The a/c switch assembly is the first place to start your investigation, as it controls all the opening and closing of the air flow vents.

JoeB