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Air Condition comes and goes during long drives

2K views 6 replies 5 participants last post by  speeddmon 
#1 ·
I have an 03 Murano and noticed that my AC seems to become less powerful the longer I drive the car. For instance if I drive the car for over an hour or so straight the air becomes less powerful coming out of the vents. I noticed it on a recent trip from Orlando to Panama City. I usually keep it at level 1 or 2 and it's fine but about an hour or so into the trip it felt like nothing was coming out. I decided to go up a level and a little more air came out but then it did the same thing. I repeated this process until it was at max level and it felt like it was on level 2 or 3.
When I reached my destination I sat for a while and then had to go somewhere and the air was back normal. I tested the freon and everything is fine, no obstruction with air filters. While driving around town it works fine but when I headed back to Orlando it did the same thing. It even did it on a trip to Tampa which is about 90 min away. Has this happened to anyone before or know what causes this problem? It's summer time in Florida so I really don't need this issue popping up lol.
I'm just curious before I ask a mechanic to look at it since it works fine for them and only when I drive the car continuously out of town.
Thanks
 
#3 ·
Thanks for replying but getting cold isn't the problem. The problem is that the air stops blowing over time. I'll turn it to max setting but it feels like it's on level 1 or 2. I had checked it before with a gauge and it's full of refrigerant or freon my stepfather says.
 
#4 ·
your problem can only be one of two things, the blower motor, or the blower motor resistor.

Normally if the blower motor resistor is going out, you will have speeds on your blower go out, for example, level 1 will stop working, but all other levels will still work. Then Level 2 will stop working after some time, so that you now have level 1 and 2 out but all others still working.

The blower motor normally will start making noise, will have hard time starting, or will not work at all. If you tap on the back side of the blower does your speed go back to normal?

I see this thread is over a month old, did you end up fixing?
 
#7 ·
Not yet. I went for my oil change on Friday but they were too busy so I have to reschedule and will ask them then if they know what causes this. Not sure where the blower is at or if it's making noise but I will see if their answers are similar to yours. Thanks for the input.
 
#5 ·
Air may be icing up

I had a similar problem this week with my ac. The fan is running but the volume of air coming out of the vents is greatly reduced. What I ended up doing is turn off the ac and let it run on vent only drawing in air from outside.

The flow began to increase and even though the temperature was in the high 80's, the air coming out of the vents was cold. After a bit I had full air flow again and the ac worked fine.

It is my understanding that keeping an ac unit on recycle or Max-ac for an extended period of time can cause this to happen. I may be wrong but it worked for me.
 
#6 ·
Usually when the blower works but cool air stops, the AC unit is building up ice because it's not cycling on and off. When the ice builds up on the cooling surfaces, it can't blow cold air past. When the AC turns off and the ice melts, you start getting cold air again.

Have the AC checked and make sure it has a full charge and is working properly.
 
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