How can I fix my heater / AC unit in my 1999 Buick Park Avenue ?

Question

I own a 1999 Buick Park Avenue, 3.8 L, V6, Base Model, the defrost work fine, but the " heater " part does not. When I drive out in the highway and I put the tempeature setting at say 74 or 75 degrees F it just sits there and does absolutley nothing - no heat !
Alot of times, there will be this " ticking / clicking " noise as if the blower motor is trying to do something.
The other day we were driving approx. 140 miles one way and it was 58 -60F outside temp and we wanted to 74 - 75 inside the car and I stopped and poped the hood of the engine and here all the various connections ( on the ends ) were all frosted up with white frost on the outside ! We had our mechanic replace the theromstat - but that did not change anything. The AC sometimes will work great and other times it will " roar " and the motor is " blowing " like crazy but no cold A/C coming out.
I just want to get this fixed for the wintertime so that my lovely wife is not freezing and the windows are not all frozen up. We live in PA.
Any suggestions of what might be happening and how to cure this issue ?
It's a 1999 Buick Park Avenue, 3.8 L, V6, Base Model
VIn # 1G4CW52K6X4645497
Thanks kindly!
Can I get any parts etc. from a reliable / reputabe auto junk yard ?
Or should I deal with brand-new parts ?

David

Answer 1

Your frosting problem with the AC is due to an overcharge or restricted orifice tube but it has nothing to do with your lack of heat from the floor. If I am not mistaken your heat/ac control is all one unit and all electronic, I would try a larger junkyard with newer cars that way they are still very active in the used parts business. Be careful not to break the plastic clips that secure the duct-work cable.

Answer 2

It sounds like one or more parts in your climate control system is not functioning properly. Since you indicate that your defrost works is a sign that the system functions correctly in that mode. In defrost mode, the a/c is on to dry out the air. When you are switching to heat mode, the a/c lines are frosting up due to the lack of air blowing across the evap coils. It sounds like the air duct door to divert the air from defrost to floor/vent modes is stuck/broken. It could be the door itself or the climate control malfunctioning. I would suggest that you take it to a dealer for a diagnosis and estimate. It may be cheaper to have them do it instead of trying to figure it out yourself.

Answer 3

ac is one unit lone nothing to do with heat from coolant system

heater control switch vacuum leak which control a door that control how one gets heat from coolant



ac unit runs by refrigerant different system different controls



find a better shop or mechanic



thermostat controls how the motor heats or cools by holding coolant in radiator doesnt have much to do with either system only if its stuck open and cars coolant doesn t get hot check the switch that you move from heat to ac most likey thats what not working

Answer 4

problem 1...replacing thermostat for no reason...frost was a sign of incorrect "134R charge and or compressor problem

2 find a AC guy or go to [i hate saying it] dealer..mechanics actually have special tools/test equipment and most went to school to learn AC.