This is really getting frustrating and the heat index where I live is over 100 everyday here of late. I will try and best explain my air conditioning problems best I can. First off the compressor comes on, I have Freon, and the AC lines get cold. Now if I turn my AC on low when I first start the car it can adjust it to high and then it works most of the time. Sometimes when I am driving I can do the same trick by the success rate is much much lower. And other times I can be stopped at a light, shut off the car and get the AC to come on low and then turn it up where it is working perfectly. Sometimes (rarely) the temperature readout blinks and that is when it seems to be in the process of working. Now when my AC does not work the vents are very quick to switch over to where I have them set and that is on the front panel. So basically I will have hot air blowing straight on me very quickly. But when the AC works it starts out on the legs and takes a short while (a minute or two) to transfer to the front panel (even though that is where I have it set to from the start). But I can feel the cold air on my feet in the meantime. Any and all help will be greatly appreciated as I am posting this the heat index is lower then it has at only 100. One last thing, I am getting a P0420 code error can that be related to my problem?

Thanks, Jack

It almost sounds like it might be your programmer. But, I'm not all that familiar with the newer digital climate systems yet.

Here'* the info on that code of yours...

P0420

Thanks for the info Mike. I can very easily replace the programmer with one from the yard if I knew where it was. I will search the forum for it now but in the meantime can anyone tell me where a programmer will be located on a 99 Bonneville. And what years can I replace a 99 Bonneville'* programmer with. Another words will a programmer from a 95 Bonneville work and is it located in the same place?

Thanks

Are you saying the cooling quits because the compressor turns off? Is there cool air coming out the defroster instead of the vents--or does the air flow go warm. That could be low freon charge. That would cause a flashing indicator.

Does the air flow switch from dash vents to defroster with a small amount coming out the floor? That'* the vacuum connector on the corner of the programmer box with the nipples that suck shut blocking vacuum tot he defroster diaphragm and to the floor diaphragm. OR you are losing vacuum due to bad vacuum hoses under the dash from the UIM next to the brake booster hose to the accumulator area at a T where one branch goes to the reservoir bottle (check hoses and bottle for crack) under the right front fender in front of the wheel, and the other branch of the T goes inside the car through the firewall.

And a slipping electrical actuator can give the flashing readout because the programmer isn't able to control the movement like it should do. That'* likely a cracked gear inside the upper actuator that moves the door for the passenger side air mix.

No the compressor is on and I still get no cold air. When the AC is working the temperature readout is blinking at first. I also have the most success getting the AC running from when the car is off. If I try to turn the AC after the car is driving I have little to no success. Sorry for the confusing details.

Okay so I had 1 busted vacuum line that I fixed and replaced the hoses on a couple of others. I took out the programmer and saw nothing wrong. The compressor is definitely working, the AC line gets cold, and I am full on freon. Now I did a little experiment so maybe someone can identify the problem from this. So I was on a short 1 mile drive and I did the little trick to get the AC on. I started the car and put the AC on the lowest fan setting. What happens is the cold air just dribbles out on the floor even though it is set for the dash. Now after I start driving I turn the AC on full and then it eventually comes out the dash. So what I did was when stopped at a stop sign, I turned the car off for a second, restarted the car, and now the air was blowing hot and no matter what I did I could not get cold air.What does this mean, that programmer was a pain in the *** as well as some of the vacuum lines and still I have this problem. I am about to give up and take the car in.

Jack

Jack, what year and model car do you have?

99 Bonneville SSEI