Weird A/C happ’n. Anyone had similar?

Just after I accelerated very hard to get around a slower car I started to feel warm air coming from the vents. I readjusted the A/C controls from Auto to Manual but it didn’t go away. About 1 mile down the road the A/C started to blow cold again. It only lasted about another mile. This was in 25 to 45 mph traffic in the mid afternoon, maybe 90 to 95 degrees outside. This kept going on for about 15 miles. In fact I started resetting the trip OD just to see if it was periodic and it was.

It didn’t seem to make a difference where the controls were set it still would cycle between cold and warm air blowing about every mile (or about every 90 seconds).

Today as I was taking the car into the shop for the mechanic to look at it, it never cycled between the warm and cold settings. Same time of day about the same route but in reverse. In fact it was getting real cold in the car. Tried all the temperature control settings to make it fail but couldn’t. Seems like an electrical thing, maybe a relay or loose connection.

So, has anyone had this experience before?

FYI

Got the car back from my mechanic. He found the little blue A/C relay bad that resides behind the glove box. Replacing it fixed the warm/cold cycling problem that I was having. Also added dye and a can of freon stuff. Well see if it holds or leaks dye out.

Sounds like you are low on 134a. The increase in engine RPM depletes the available 134a you have in your system. More than likely you have a leak, the systems are sealed. You can verify this by starting your car with the A/C on max, then raise your hood and look at the clutch on the compressor, then reach under the black plastic cover for your throttle body and increase your engine RPM, more than likely you will see the clutch on the compressor open.

Thanks, I'll give that a try. It just seems odd that it is so peroidic even after the sudden burst of acceleration, for it was doing it at a constant freeway speed of about 45 MHP as well.

I couldn't find a sight glass to check for air bubbles in the system like on my older cars with R12. Is there one?

No sight glass- you have to check with a pressure gauge. I recharged mine last summer with a kit from an autoparts store- very easy to do. Now let's just see if it held over the winter.