AC works on highway only

95 toyota tercel, AC works great on highway at about 55mhp or higher speeds.

Issues start when i drive within city limits, and especially when i hit a traffic light or have to wait in drive thru for about 5min.

Then I don’t get any cool air. In previous years the AC would click on again once I start moving. This year I have to stop and leave the car for about 15/30 minutes before i can get the AC to ‘click’ on again.

Your thoughts are appreciated. Freon was filled up about 5 days ago (1.5lb)

If you are not leaking refrigerant, then I wonder if the amount of air pulled through the condenser isn’t sufficient due to a bad cooling fan. When you are traveling above 55 mph, enough air may be blowing over the condenser to disperse the heat. If the fan isn’t pulling enough air through the condenser at lower speeds, the air conditioning may not work.

However, when you say that it “clicks on”, this almost sounds as if the system is losing its Freon charge. When you had the system refilled 5 days ago with 1.5 pounds of Freon, did you find any leaks?

no leaks found. even at lower speeds it works, but seems to really stop at a ‘stop’ sign. and then takes long time to start up again.

Are both cooling fans running when the A/C is on? You should be able to tell by turning the A/C on; openning the hood; and eyeballing the fans. The system has an overpressure cutout switch that would trip if there were no airflow going through the condensor. I am sure that the shop that serviced the A/C would have checked but make sure that there is no debris, like leaves, bugs, dirt, mud, etc., on the front of the condensor (that is the part that is placed ahead of the engine radiator).

Hope this helps.

We really need to know what both the high and low side pressures are; preferably at idle and elevated RPMs both.

The car is going on 15 years old and if it took a pound and half of refrigerant it’s got a fairly major leak that needs to be repaired.

Over or under refrigerant charge, electrical glitch with a pressure switch, inoperative fans, expansion valve problem, etc. are possibilities but without knowing the pressures it’s anybody’s guess.