when i accelerate in my buick roadmaster my ac compressor shuts off i disconnect the battery and reconnect and the ac starts again what can i do to fix the problem i dont know why it keeps shutting of

Asked by Oct 01, 2013 at 09:21 PM about the 1991 Buick Roadmaster

Question type: Maintenance & Repair

ac compressor keeps shuting off

7 Answers


A few things to check. 1.) You may have to much refridgerant in your a/c system. The high RPM causes a high output pressure from the compressor and shuts it down. The a/c system will have two pressure switches a high and low (for over pressure and low fluid). 2.) Another cause of the spike could be a partial blockage some where in the system. An a/c recharge kit comes with a fitting and gauge that would allow you to check your line pressure to narrow down the issue. Since you make it sound like it starts working after you leave it shut off for a while I doubt that it is a loose wire. Before it shuts off does it work, is it blowing cold air.


There is an A/C cutout that is activated when the throttle reaches a certain point just past 3/4 throttle but the A/C should kick back in when you get done accelerating and return to a cruise condition, on this model I believe that it is controlled by the ECM so you may want to at least have the systems codes checked.


I have only heard of that on newer cars and usually the performace versions. I doubt the 1991 Buick had this feature, but maybe. Even if it does it's sounding like it needs time for the high pressure switch to reset before it allows the comp to kick back in. Blockage would be the most likely cause unless it was just recently re-charged with to much refridgerant.

1 people found this helpful.

If you have not had any A/C work done, and the car has electronic climate control, odds are that it is LOW on refrigerant. The controller will disable the compressor until it is reset. Have someone check the a/c system with a pressure gauge set. Stop disconnecting the battery. If the system is low on refrigerant, the compressor can be damaged by forcing it to run with a low refrigerant charge. The refrigerant circulates the lubricating oil for the compressor.

1 people found this helpful.

I recover the systeme and recharger with 1.80 lb of freon 134 the low pressur is 30 psi and the Hi is 180 psi look to me I have some problem with the ground because went I reset the A.C work perfect if I drive the car easy the ac work until I step on the gas


Your pressures and charge are too low. Original charge calls for 50 ounces of R-12 refrigerant. See the attached link: http://acpartshouse.com/refrigerant-and-oil-capacities/abcd When converting to R-134a, you use only about 80% of this number, which is 40 ounces. 40 ounces = 2.5 pounds of refrigerant, not 1.80lbs. You are 11.2 ounces (or .70 lbs) low on R134a.

1 people found this helpful.

Ok I will try that thanks

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