AC Not Cooling Cabin (Replaced Compressor)

[whitejeep05]

Hey y'all,

I am having to do a lot of repairs on this new jeep. One of the big fixes I have been working on is getting the AC fixed. I had a shop replace the AC unit all together but it's still not adequately cooling the cabin when it's hot out. When it's cool out then it actually cools the cabin fine.

I had the tech use an infrared thermometer when it was hot out, and the vents were reading ~60deg+. The reading is ~40-50deg when it's cool in the morning which is quite cold.

Could my cabin blower motor not be strong enough? Is this a matter of the AC unit just not cooling efficiently enough in heat? The only thing I haven't replaced is the AC condenser. Could this be the cause of it not cooling efficiently in the heat?

Thanks

 

[uss2defiant]

was it pretty humid out?
what was the ambient temperature?
what were the pressures?
Does it get colder when moving vs. idling?

AC has a lot of parameters to consider.

 

[Billwill]

Hey y'all,

I am having to do a lot of repairs on this new jeep. One of the big fixes I have been working on is getting the AC fixed. I had a shop replace the AC unit all together but it's still not adequately cooling the cabin when it's hot out. When it's cool out then it actually cools the cabin fine.

I had the tech use an infrared thermometer when it was hot out, and the vents were reading ~60deg+. The reading is ~40-50deg when it's cool in the morning which is quite cold.

Could my cabin blower motor not be strong enough? Is this a matter of the AC unit just not cooling efficiently enough in heat? The only thing I haven't replaced is the AC condenser. Could this be the cause of it not cooling efficiently in the heat?

Thanks

AC Condensor could be the problem.

If your previous compressor seized up it could have deposited a lot of metal pieces inside the system which could block up the system.

Are all the vents blowing air out correctly ie. the demister vents, dash vents feet vents etc. This is controlled by a vacuum pipe from the intake manifold to the vane control behind the dash....if this vacuum pipe comes off or has a split in it then air only blows out of the demister vents.

On a cool day with the AC OFF and cabin heater set to OFF....is the air blowing into the cabin the same as the outside air or is it warmer? I am concerned that the heater may be heating up the cabin at the same time as the AC is trying to cool it down.

Check the AC radiator up front is not clogged up with dirt and if you have an electric fan there check that it is working.

There is no cabin pollen filter on the KJs but there is a metal grid inside the cabin against the firewall under the glove box....this gets clogged up and mainly causes problems on re-circulating the inside air but it could have some effect on normal cooling. Have a look for this metal grid and clean it nicely....some KJ owners cannot find this grid there under the glove box...some year models may have moved it somewhere else!

 

[ThatsMrGimp2U]

AC Condensor could be the problem.

If your previous compressor seized up it could have deposited a lot of metal pieces inside the system which could block up the system.

Are all the vents blowing air out correctly ie. the demister vents, dash vents feet vents etc. This is controlled by a vacuum pipe from the intake manifold to the vane control behind the dash....if this vacuum pipe comes off or has a split in it then air only blows out of the demister vents.

On a cool day with the AC OFF and cabin heater set to OFF....is the air blowing into the cabin the same as the outside air or is it warmer? I am concerned that the heater may be heating up the cabin at the same time as the AC is trying to cool it down.

Check the AC radiator up front is not clogged up with dirt and if you have an electric fan there check that it is working.

There is no cabin pollen filter on the KJs but there is a metal grid inside the cabin against the firewall under the glove box....this gets clogged up and mainly causes problems on re-circulating the inside air but it could have some effect on normal cooling. Have a look for this metal grid and clean it nicely....some KJ owners cannot find this grid there under the glove box...some year models may have moved it somewhere else!

Exactly this.

 

[whitejeep05]

AC Condensor could be the problem.

If your previous compressor seized up it could have deposited a lot of metal pieces inside the system which could block up the system.

Are all the vents blowing air out correctly ie. the demister vents, dash vents feet vents etc. This is controlled by a vacuum pipe from the intake manifold to the vane control behind the dash....if this vacuum pipe comes off or has a split in it then air only blows out of the demister vents.

On a cool day with the AC OFF and cabin heater set to OFF....is the air blowing into the cabin the same as the outside air or is it warmer? I am concerned that the heater may be heating up the cabin at the same time as the AC is trying to cool it down.

Check the AC radiator up front is not clogged up with dirt and if you have an electric fan there check that it is working.

There is no cabin pollen filter on the KJs but there is a metal grid inside the cabin against the firewall under the glove box....this gets clogged up and mainly causes problems on re-circulating the inside air but it could have some effect on normal cooling. Have a look for this metal grid and clean it nicely....some KJ owners cannot find this grid there under the glove box...some year models may have moved it somewhere else!

Thanks for the great tips.

I'm going to test the AC/Heater OFF and see if there's a difference in temperature with ambient. What could cause the heater to also be heating while the AC is running? How could I solve this? Would this be related to the common HVAC door issue on these models?

I am getting air through all vents but I will check the vacuum line there. I did have a large blockage on the metal grid behind the glovebox which I cleared and allowed recirculation to begin working normally again.

I have checked the condenser up front and it doesn't have any major blockages in it, air seems to be flowing through it. I am seriously considering replacing this as the last major component in the system. I'm worried that I will replace it and still be in the same boat however.

Can blockages in the system from a previous compressor failure be purged from the system? That is what my mechanic is hoping will take care of this, but I'm skeptical of it myself.

 

[Billwill]

Thanks for the great tips.

I'm going to test the AC/Heater OFF and see if there's a difference in temperature with ambient. What could cause the heater to also be heating while the AC is running? How could I solve this? Would this be related to the common HVAC door issue on these models?

I am getting air through all vents but I will check the vacuum line there. I did have a large blockage on the metal grid behind the glovebox which I cleared and allowed recirculation to begin working normally again.

I have checked the condenser up front and it doesn't have any major blockages in it, air seems to be flowing through it. I am seriously considering replacing this as the last major component in the system. I'm worried that I will replace it and still be in the same boat however.

Can blockages in the system from a previous compressor failure be purged from the system? That is what my mechanic is hoping will take care of this, but I'm skeptical of it myself.

The general consensus is that if a compressor seizes up then all the other components including the piping need to be flushed out of debris before fitting the new compressor.

Download the 2005 KJ Service Manual here and read up the theory...Section 24... on how the AC/heating system works.ie. the HVAC system:

Index of /manuals/Jeep/KJ