Last year on a long trip during very hot weather, my 2003 Honda CR-V’s A/C out temperature dropped and I could notice what I felt was humidity or moisture in the air in the car via smell, the air just seemed to go mist. A few minutes later it went back to cold, but it get doing this as I drove. Honda say nothing wrong with the A/c and suggested I keep the one switch in re-circulate so I would not pull in outside air. They also suggested re-charging the system, but I felt if the system were low the output would be constantly warmer than expected, not vary. Leaving it on re-circulate seemed OK until yesterday, it was 95 or so, I was going down the interstate, and the output started changing again even though the re-circulate was on.
Looking for any thoughts on this. Does it sound like recharging the system would correct this? This typically happens on the Interstates when I am travelling fast - I can’t recall it happening in city driving. I can’t make it happen so I feel that wherever I take it they will see nothing wrong and suggest the re-charge.
My guess is that moisture in the air froze on the evaporator coils. The air conditioning compressor switched off to let the ice melt. The compressor then switched back on. This is the way it should operate.
A low charge condition should be checked by attaching the manifold gauges to the system. Did the dealer do this?
You might want to look at the front of the condensor for bugs and debris that may be blocking air flow to the radiator. The AC system in your vehicle has a coolant temp sensor. If this sensor detects that engine is on the verge of overheating it cuts power to the compressor clutch so no more heat is produced from the condensor and it reduces the load on the engine. This then allows the engine to cool back down. But you lose the AC. Once the engine cools back down the sensor allows power back to the compressor clutch and the AC returns.
The reason this happens at highway speeds and not while driving in town is, at highway speeds is when the engine runs the hottest. And if the restricted condensor is blocking air flow to the radiator the engine will start to run hot. While doing in-town driving, the engine doesn’t run as hot and electric radiator fans can remove the heat fast enough to prevent overheating. So the AC works all the time.
I don’t believe the dealer checked the charge since they just mentioned charging it as a possible fix, no mention of being low of refrigerant was mentioned either. I’ll also check for the Air flow blockage. That sounds interesting since this didn’t start until a year ago.