Does anyone know how to check whether a Air Programmer works? Or do you know somewhere to send it to be checked. I've installed a used Air Programmer recently and the air compressor still doesn't turn on. Any help would be appreciated since this problem is about to bankrupt me.
Thank you
Wade

 

I see you a very new member. You need to identify what year the car is. The C4 spans 12 years with many differences. Without knowing the year, no one can help much. Filling out your profile would be an additional help also.

Obviously you’re A/C compressor does not run which is your main problem. Please also say if you have a manual or automatic system. There are many things to check once your year is known. Need to know exactly what you changed and where it is located in the car. Knowing the correct terms and names of items is a great help. We will try to figure that out with your help.

 

This is a 1995 convertible. It has an automatic system.

I have replaced the Heat/AC electronic control panel, the sensor on the low pressure hose and the compressor relay located on the inside of wheel well on passenger side. The compressor would not kick on.

I took the car to local Chevy dealer, who put it on computer and told me it needed a Air Programmer, located under the dash. At the dealer, they were able to turn the compressor on by sending signal.

I purchased a used Air Programmer, I just plugged in the cord and compressor will still not turn on. Do I need to connect the 5 hoses before the Air Programmer will work or should the compressor work with just the cord plugged in?

I have the correct pressure but no signal running to the compressor to turn it on. I checked the compressor and it runs well and puts out cold air.

Is there anyway to check/test this used programmer to see if it is functioning properly?

Thanks in advance for any help?

 

You do not need to connect the vacuum hoses to get the compressor to engage. The hoses will only change the vent configuration. The electrical connector does is all as far as the electronics go.

There no real way to check the programmer (under dash) other than to install it in a car.

If the used programmer (under dash) is good, then you have not found the cause of the problem.

Do you have any flashing LED lights on the control head (unit in dash). I assume you don’t since you have not indicated the button lights are flashing.

I would first jump out low pressure cycling switch (the one you replaced). Remove the connector and connect the terminals and see if the compressor starts.

Check fuses 1, 5, 18 and 43.

The PCM is also involved in closing the relay for the compressor. Maybe there is a bad pin connection in one of the connectors.

The dealer closed the relay on the compressor, how did they do it. I would think that would have told them something.

I will see if I can get some schematics for you to look at tomorrow.

 

Dealer used a Tech 2 or similar which emulates the Controls and sends a Digital signal via the CCM Link to the Programmer to see if it works. If it does, it's usually the Control Panel and not the Programmer. I'd do something simple first - disconnect and reconnect the Battery. That'll remove any memory glitches or stored trouble codes and it might just work after you do that. If not, there are 2 serial data lines from the Controls to the Programmer - unfortunately, I don't know the colors - but you want to make sure they're intact; ie, ohm out those wires to verify a completed circuit. Next, if you have a Scanner, check the Pressure Sensor signal. Should be about .8 volts or 80 psi on a 70 degree day. Finally, follow the procedure for troublecodes and get the Data Stream and post what it's showing for each parameter.

 

Here are some pictures of the AC system. The first one is all the basic players to start the compressor. The second and third have more detail (connections) of the system configuration. FYI - Drawings are for a 94.

I assumed you would say Tech 1 or 2 or some sort of scanner, but just curious if you knew the exact item they used.

With this info you might try to follow SunCr advice and direction.

 

I checked the fuses today all 4 of the fuses were good. Tried to jump the compressor off at the low pressure switch but nothing happened. I have 6 volts at the lowe pressure switch. I can run a hot wire to the compressor and it will cut on and cool very well. Checked my pressure in the system and it was 50psi. Is there any way to check the air programmer to see if it working correctly? This car has only 30,000 miles on it, this is so fustrating. I do think you for your help. Any other ideas I hooked my scan tool tothe car today it showed no codes.

 

This problem is going have to be troubleshoot trying to eliminate what is bad and what is functioning. Divide and conquer, replacing parts doesn't seem to be the right track since there are almost no parts left to replace. So let's try to figure out what might be good, bad and what we can make work. There are many ways to approach this problem. I will give you a plan to see if we can make some headway.

**On the control head, are there any flashing LED lights, and do the LEDs light when you push the buttons?

**Have you disconnected and reconnected the battery as suggested?

**You indicated you checked pressure in the system at 50 psi. Did you use a set a gauges and was this the static pressure of the system? (both low and high read the same when system is equalized (compressor not engaged for a good while)). Because if that is you static pressure, it sounds low. It should be about 75 to 95 psi depending on ambient air temperature.

1) Remove the cycling switch connector and ground the DK GRN/WHT wire # 762. See if the compressor will start. If it does, the PCM is working correctly and all the inputs to it and sensors are probably OK. If it does not start, then that area has to be troubleshoot. This will have to be done with the engine running.

2) Select A/C to on. With the connector of the cycling switch still off, take an ohm meter and measure the DK BLUE wire #204 for continuity to ground. This will have to be done with the engine running. If it is open that verifies the programmer is not giving the signal to the PMC for A/C request. (Normally it should read near ground).

If you had compressor start on (1), and open on (2), then;
Look at the control head connector and the programmer connector for any pushed pins or corroded pins. Check the DATA wires as suggested if possible. Wire # 835A & 835B.

 

R134 at 50 psi static is like 54 degrees. Either you don't need a/c, or it's out of gas - or your gage set is inaccurate. Confirm the gage reading with your Scanner; ie, what's the Pressure Sensor signal? If it's 50 too, you're out of juice assuming it's 70 or better which is when most of us get concerned about a/c.

 

A point well taken in regard to the data lines. But he can control the fans and speed and control over vents. That would indicate the control head is communicating with the programmer. If the programmer is good (and he has 2 of them) the switch at terminal C6 should be closing to ground. (Have had personal email info)

If this is all true, the problem is elsewhere as to why the PCM is not activated to close the compressor relay and start the compressor.