AC Pump turns off and on

[sjtilney]

05 Liberty sport 4x4

The other day I was recharging my ac. I turned the ac on and began refilling, I noticed while I was recharging it that the pump kept on turning off and on. It would stay on for about ten seconds then turn off for about 5. If was doing this for about five minutes then it stayed on with out going off. When ever it turn my ac on while driving I can hear the pump turning off and on. Is it supposed to do that? Could it be a bad relay?

 

[WireEd]

I had a similar problem in a Ford Crown Vic I drove on a long trip. In my application there was a high pressure sending switch that failed. It is supposed to allow the system to run up pressure then shut off. Mine shut the system down most of the time which reduced my ac. I pulled the connector and briefly bypassed the pins with a jumper (manually shut the system off periodically). This allowed me to verify the ac was actually working, which it was. Ultimately, the switch allows the system to build pressure to a point, then shut it off. The result is you don't get huge swings in pressure that could damage the system. If it were to freeze up it could sieze your compressor.

To answer your question, it is good that the compressor cycles on and off. BTW, if the compressor runs all the time it could be an indication it never reaches full pressure which might mean a leak or at least not enough refrigerant.

 

[2003KJ]

On an 05 you shouldn't have to recharge the system just yet, unless you use it a lot or you've got a leak somewhere.

 

[jeepkj02]

On an 05 you shouldn't have to recharge the system just yet, unless you use it a lot or you've got a leak somewhere.

How often are you supposed to do this?

 

[JeepJeepster]

^If you dont have a leak then not for a long, long time.

If the poster didnt have a leak then its probably over charged now.

 

[tjkj2002]

Mordern A/C systems have a cycling clutch,so if it goes on/off that is normal and long as it doesn't cycle on/off every few seconds and always does that and not blow any cold air,then you are undercharged or have a bad low/high pressure switch.

The clutch will cycle off when the evaporator get's to about 34-35 degrees to prevent freezing up the evaporator.

 

[2003KJ]

How often are you supposed to do this?

It really depends on how much you use the system. For example, I just recharged the system on a Chevy a couple of weeks ago with the automatic dual climate control. The truck has 116,*** miles on it, and is a 2004 model. With the auto dual climate control, the a/c never goes off...even in the winter, it's constantly cycling. So all that mileage equates to a couple more years of "use" than say a vehicle thats driven an average of 15K/year that hit 115.

Like Blake said, and this is what I was getting at, the system is probably over charged now.

 

[Mangate]

This is the only problem I have had with th Liberty. The gas has escaped twice, both times after being away and not using the vehicle for at least 2 months. Even the ink that was put in after the first refill did not show up the leak. When it was low on gas the clutch would cycle on and off much more rapidly than normal.

 

[2003KJ]

This is the only problem I have had with th Liberty. The gas has escaped twice, both times after being away and not using the vehicle for at least 2 months. Even the ink that was put in after the first refill did not show up the leak. When it was low on gas the clutch would cycle on and off much more rapidly than normal.

With a leak that big, I find it hard to believe they couldn't find the leak...

 

[JeepJeepster]

With a leak that big, I find it hard to believe they couldn't find the leak...

Maybe its hidden.. Behind the dash maybe?

 

[2003KJ]

Maybe its hidden.. Behind the dash maybe?

That would suck big time if it's the evaporator leaking....

 

[jeepdaddy65]

I had the same think going on with my 05 Renegade. I was told on one forum it was a normal thing for 05 and up Libertys. My A/C works good. Mine cycles every 20 sec or so and stays on for about a minute. no matter where the selector switch is on the dash, thats what got my attention, normaly I have heard other vehicles only cycle on A/C or defrost. But again I was told this is normal for the newer ones, something about keeping the seals lubricated.

 

[tjkj2002]

something about keeping the seals lubricated.

That is one reason for the A/C cycling on defrost setting,also it helps dry the air out which helps keep the windows from fogging up.

The older cars that did not have this feature the A/C pump clutch seal would start leaking after a few months of not being used.

 

[jeepdaddy65]

your right there, I had to do a lot of work on the A/C units on my old cars. The thing that bothers me is on my liberty it cycles even when its set on the floor position or any other selection on the dash. I also have a button on my dash right next to the rear defrost that turns the A/C off and on. Even with that off mine cycles.

 

[JeepJeepster]

your right there, I had to do a lot of work on the A/C units on my old cars. The thing that bothers me is on my liberty it cycles even when its set on the floor position or any other selection on the dash. I also have a button on my dash right next to the rear defrost that turns the A/C off and on. Even with that off mine cycles.

05+libertys turn the A/C on when its on the floor, defrost/floor, or pure defrost modes. This is 100% normal.