93 roadie a/c not working

works great for the first 2 minutes ,then no power to the compresser. I swapped out the blower control module and the ecm . anyone have any ideas?

Low freon?

Likely that the low pressure cut off switch is to blame. Temporarily jumper the connector to bypass the switch and see if it keeps running. If it does, keep in mind that the switch may be doing it's job and may be indicating a system pressure issue. Or, the switch is bad.

Something else to check is the A/C relay. Should be mounted next to the fuel pump relay under the hood by the firewall.

I wrote a long primer on our AC system: http://www.buickforums.com/forums/showthread.php?t=26737

From what you describe, I would suspect a blockage in the system causing extremely high pressure, tripping the high pressure cut-off. Or low refrigerant causing a low pressure condition when the compressor draws it down. Does the system cycle?

What you need is to check the pressures with a gauge set. If you can get ahold of a proper scan tool, check the raw data stream on the HP switch. Once you have some idea of what is going on, look at the second last post on the second page of that thread for some troubleshooting tips.

buickwagon wrote:

I wrote a long primer on our AC system: http://www.buickforums.com/forums/showthread.php?t=26737

From what you describe, I would suspect a blockage in the system causing extremely high pressure, tripping the high pressure cut-off. Or low refrigerant causing a low pressure condition when the compressor draws it down. Does the system cycle?

What you need is to check the pressures with a gauge set. If you can get ahold of a proper scan tool, check the raw data stream on the HP switch. Once you have some idea of what is going on, look at the second last post on the second page of that thread for some troubleshooting tips.

Is there any other way you write!?

The AC tutorial is admittedly long even by my standards.

Jeff, I have a set of gauges if you need 'em

pressure is fine, it blows cold for a few then the comp stops

Does it still have voltage at the connector when the compressor stops? If so, is the ground still good at the connector?

59 wagon man wrote:

pressure is fine,

What are the pressures (high and low) when it quits? Does it cycle back on eventually, only after sitting for a while, immediately after cycling the key, or ???

He told me if he turns off the motor for a couple minutes, on star it'll run again fine for a couple minutes then the compressor stops, blower still blows. I suggested swapping the relay module under the dash with the parts car he took the motor from as the AC was working fine in that one. I assume it didn't help as he posted several hours after we spoke.