need help with a/c, 83 Buick Prk Ave

Hi Guys: I have a problem with an 83 Buick Prk Ave. I've been trying to restore ( need some good help ) I put a new a/c system in and afterward we tried the unite but it would not work the way it should. Now I have the shop manual and after going over the unit we decided it had to be the touch control unit in the dash. Now the book says you can't swap the touch control I guess their unit specific each car sold has it's own. But I tried to swap one out and it did not work. Now I don't know what to do the only thing I can think of is ( Vacum ) . Did anybody ever run into this problem because any help would be greatly appreciated I would appreciate any feed back!!!! I'll say thanks in advance!!!

I guess we can start with the basics. Specifically what is wrong with the system? What is it doing or not doing? What have you done so far? Give us some idea of what is going on and we can help.

What was the original reason these repairs were needed? With the original touch-control unit, what would it do or not do? It is possible the touch-screen units were "model year specific", but I don't recall them having a computer in them which had to talk to the BCM, back then. As Larry mentioned, we'll see what we can come up with.

Please advise,

NTX5467

Well Guys: When I bought it the actuator door lights would blink no matter what temp u used. Heat kept bleeding through the compressor never kicked in. So I replaced the comp, a/c lines, the whole nine yards up to the heater. We checked the system the touch control still blinked on every temp which I assumed the actuator doors still weren't closing. I got a used touch control off the net e-bay and we got the same response. No comp,no air, doors still blinked. Confused is this control tied into the E C M ? Thanks guys for your help!!!

Let's start as square one.

What was the original complaint with the car?

If it was just the lights on the control head blinking why did you replace the refrigerant system?

Could be just a bad ground for the head & actuators.

My memory is the compressor is controlled through the ECM, but would need to confirm with a service manual.

Hi Larry and thanks: To begin with when I bought the Buick the a/c didn't work , the comp. was rusted and the Freon lines and drier were in bad shape so decided to replace everything up to the heater. I took the car to my mechanic( very good ) he charged the system still nothing he called and told me it must be the dash unit, so I bought another touch control of e-bay still the same problem all settings lights would come on after a minute no comp, and with the water petcock open heat bleeds into the interior. I'm sure he check for a good ground he does work on my 2 collector cars also. Well that's about it I hope this helps sorry I can't be more help. Thanks for any help you can give!!!

Joseph,

I guess that I am at a loss to replace all of the a/c lines, compressor, condenser?, evaporator core?, receiver dryer?, orifice?,?? What exactly was replaced and why? I guess I need to understand "bad shape" Do you have any pictures?

1. If you put a set of a/c gauges on the system, what type of pressures are you getting on the high side and the low side with the ignition off?

1.1 What are the pressures with the ignition on, engine running and A/C request?

2. Is there the correct charge in the system?

3.How do you know the correct charge is in the system?

4. Are you using R-12, or R-134A, or some other snake oil?

5.Can you jump the a/c relay and make the compressor come on when the engine is running?

Lets start here.

Trying to help, but your post is confusing.

Let's start somewhere completely different.

I suspect your mechanic has checked the lower pressure and high pressure cut off switches for any voltage at all?

Thanks avgwarhauk:I can't locate your post so I'll print your e-mail. Thanks again for you help I'm planning on going over every wire again. Thanks Everyone!!!

Joseph,

Can you answer the questions that I asked above?

Seems like I recall something about "blinking" being related to a perceived loss of refrigerant gas? If the system is fully charged with appropriate gas, then under this premise, the lights should not be blinking and the compressor should actuate upon command. There's probably a pressure/cycling switch and a "pressure loss" switch in the system. I suspect that if either one is not reading pressure, then the controls perceive the system is low/empty on refrigerant gas. The "pressure loss" switch is to protect the compressor from internal damage from running without sufficient refrigerant in the system.

I suspect that what you are terming "heater" is really the evaporator coil case. The heater core is behind the instrument panel, inside of the passenger compartment.

IF the compressor had an internal problem, it could have put metallic powder throughout the refrigerant system, probably stopping at the orifice tube's filter screen. If this is the case, the new orifice can be plugged already, which would prevent refrigerant flow in the system. In such cases of internal compressor failure, GM's directive is to install an inline filter in the system, replacing it until it stops being plugged each time by residual debris in the system.

As mentioned, you should be able to "jumper" the compressor to make it engage manually to see if it works and the system can cool somewhat.

When the system operates as it currently does, I suspect the fan runs and air output can be felt from various outlet vents? Do the vents change when commanded to by the controller? Can the fan speed be varied manually?

On many of the Buick automatic hvac systems, in the a/c case under the hood, instead of a blower motor resistor coil mechanism, there's a "solid state" transistorized version instead. A transistor on a finned heat sink which takes the place of the "analog" blower motor resistor in the a/c case.

The reason the ECM is involved in the a/c compressor clutch commands is that on some models, when the a/c is turned on, it also turns on the underhood cooling fans and then modulates them as needed (if that applies to your model year of vehicle). The other "connection" is that for increased available engine power, some vehicles will turn off the a/c compressor during times of higher horsepower demands, i.e., passing maneuvers, hard acceleration, times when manifold vacuum drops below a pre-determined level. For example, if you have the cruise control operational, the vehicle encounters a steep hill, the cruise control throttles into the engine to maintain the set speed, and you notice a short period of decreased cooling, but things return to normal after the "higher load condition" ceases to exist. Almost every newer vehicle is like that, to varying degrees, but I'm not sure about your earlier model year.

On your earlier model of Buick, the GM hvac system had the instrument panel control and also had a "programmer" which made the vent door vacuum actuators work. It can be a complicated situation to troubleshoot, as I recall. Should the vacuum source be compromised, the default mode for the vent doors is "heater floor and defroster" output. On many GM cars of that era, the vacuum for the system was shared with the cruise control vacuum. Many times, the check valve for the cruise control system, near the brake master cylinder, was tee'd to supply the a/c system vacuum. They tended to get a small crack at one of the fittings, which means the cruise might still work, but the a/c vents would go to the default mode of "floor and defroster". There could also be a "black balloon" vacuum reservoir between the hvac vacuum source and the inside of the car. They were generally trouble-free, but the vacuum check valves had many more issues as the vehicle aged. If you touch it and it the vacuum terminals come apart, you've found that culprit . . . for that issue.

I'm not sure, but you might need to get a GM Body Service Manual rather than a GM/Buick Chassis Service Manual to get the a/c information you might need to troubleshoot the system? Plus, possibly, the electrical wiring schematics.

Please keep us advised of your progress.

Take care,

NTX5467

Guys I really appreciate the help as soon as I can I'm going back over the whole a/c system I will keep you all posted. ( Again I really appreciate your help if I can't fix this problem don't know what I'll do.) Everyone have a great wk/nd!!!

Joseph 44, I do not mean to offend you, but I suggest you step back from this project and source an experienced A/C repair person. The differences in the A/C systems from generation to generation can be confusing and what applies to one may not apply to another. I don't know where you are located but there are folks out there who do know what to look for and how to fix these things, while probing and replacing parts without a systematic approach is just racking up added expense which could have gone to just getting the original system fixed.

The two things you absolutely need to know right now are:

* did your mechanic charge the system with R12 Freon? And if not, what did he use? That will be what the A/C repairman will need to know.

* did you replaced the A/C Compressor with a rebuilt unit, or a new one?

NTX5467,

If my memory is correct, a bad / stuck mode door motor will cause the lights on the Electronic Touch Climate Control to blink. As well as a number of other items.

Unless the basics get answered as requested above, we are unable to help.

LS

PS, I believe the A/C diagnostics are in the Service Manual, not the Body Manual.

I was responsible for the '79 A/C section for Buick.

And you did a hell of a job on that Larry. The A/C in my 78 Wagon still works... THANK YOU!!!

Larry, it's been a good while since I had to think about those earlier systems. We did have the automatic a/c in Chevys, though, but without the touch-screen. I believe the "programmer" and mechanicals of the system under the dash were the same, though, just different dash controls?

Back then, GM had some of the best hvac units in the automotive world. Thanks, Larry, for your contribution to that.

NTX5467

There was a difference between the manual a/c on the '83's and the Touch Climate Control. I seem to think there were a couple of electrical mode door actuators instead of all vacuum. There might have been a combination/ hybrid of the two systems. Need a service manual to be sure.

I was not on the design side, just the service manual writing so the technician could fix the car.