96 PA a/c blows hot and flashes

[Knox cnty resident]

96 PA air conditioning initially starts blowing full heat and shifts to cold air after a couple minutes. The external air temperature flashes during the full heat time. What would cause this, where is it, and how do I fix it?

[HotZ28]

Has the battery recently been disconnected, or completely drained?

[Knox cnty resident]

The battery was disconnected to reset a computer code for the idle air control valve; but the problem existed prior to that.

[HotZ28]

Is the external air temp reading correct ambient temp, or is it skewed? When the display is flashing, a fault is detected. Hard to say what the problem is without a scan. Usually, the system will recalibrate after about 50 ignition cycles. You can take it to a dealer for a Tech II scan, or wait until the problem corrects itself, if it will.

[Knox cnty resident]

I believe it flashes the correct outside temp. I'll have to pay a little more attention. It has been flashing 68 in the morning which is about right.

[688i]

My 96 PA is doing the same thing as mentioned in this thread. It was blowing out of the defroster and I did the vacuum connection mod described in an older thread that is required when the connector nipples are soft and flexible. (Sounds like old age sex) After I did the mod it has been acting like this thread describes. Only thing I'm not certain of is where the bottom switch lever arm that is operated by the programmer should be set. I'm not sure I set it back in the same snap location after reinstalling the programmer. Is there a proper way to set this lever snap connection? This board is amazing and has saved me hundereds of dollars in repair bills. I am most grateful.

[eharri00]

when I turn the vent on in my 1995 buick Park Avenue, it blows out very weak and blows from floor, vents, and window and it's very weak. Is it the A.C./Heater control assembly? I fully charged the A.C. and the lines in the engine are cold.

[688i]

You need to search this forum and find the link to the programmer vacuum connector repair and or modification. Sounds like your vacuum connector nipples have gotten soft and flexible which causes sporadic closing which bloks the vacuum of to your dampers. I just did the mod-repair option which involves removing the programmer, cutting the vacuum lines off the bad connector and rejoining them back together with 1/8 vacuum line.

[Knox cnty resident]

Originally Posted by HotZ28

Is the external air temp reading correct ambient temp, or is it skewed? When the display is flashing, a fault is detected. Hard to say what the problem is without a scan. Usually, the system will recalibrate after about 50 ignition cycles. You can take it to a dealer for a Tech II scan, or wait until the problem corrects itself, if it will.

It does indeed flash the correct outside temperature