[chris7874]

Ok i have a 2003 Grand Cherokee Laredo 4.0 with manual A/C controls. The A/C blows cold like it should but only for about 15 minutes. Doesn't matter if i'm driving down the highway or idling in the driveway. While it's blowing cold, the inlet pipes from the receiver/dryer and the pipe going to the compressor are cold and giving off condensation. All seems normal. Nothing coming out of the drain tube yet (don't know if that's still considered normal.) After about 15 minutes, the A/C stops blowing cold. It doesn't go hot but i'd say on the mildly warm side. Almost as if it was just a fan blowing regular air and not air-conditioned air. At this point the condensation on the a/c pipes dries and the condensation starts dripping rapidly out the drain tube onto the driveway. The compressor is running this whole time. If I turn the engine off and let it sit for a few hours, the situation repeats and I get A/C for another 15 minutes. This happens in recirc mode as well as other modes. The coolant level is fine.

Thinking it was low on refridgerant, I took it to Jiffy Lube, they did an evacuation and recharge. Afterwards, the same problem. When I took it back the next day they tried to re-do it but they told me nothing was coming out during the evacuation as if all the refridgerant had leaked out overnight. I doubt this since if that were the case, the a/c wouldn't blow cold at all, even if just for 15 minutes. Plus I would think the compressor wouldn't spin if nothing was in the system but it doesn't. Must be something else.

Reading different posts, I see where the blend doors have been a problem on my model but I would think that if they were getting stuck i'd get a constant temperature instead of varying ones.

Where I live it's been over 90 degrees for the last week or so. Unbearable without working A/C.

Anyone have any thoughts, ideas or suggestions?

[texster68]

Originally Posted by chris7874

Ok i have a 2003 Grand Cherokee Laredo 4.0 with manual A/C controls. The A/C blows cold like it should but only for about 15 minutes. Doesn't matter if i'm driving down the highway or idling in the driveway. While it's blowing cold, the inlet pipes from the receiver/dryer and the pipe going to the compressor are cold and giving off condensation. All seems normal. Nothing coming out of the drain tube yet (don't know if that's still considered normal.) After about 15 minutes, the A/C stops blowing cold. It doesn't go hot but i'd say on the mildly warm side. Almost as if it was just a fan blowing regular air and not air-conditioned air. At this point the condensation on the a/c pipes dries and the condensation starts dripping rapidly out the drain tube onto the driveway. The compressor is running this whole time. If I turn the engine off and let it sit for a few hours, the situation repeats and I get A/C for another 15 minutes. This happens in recirc mode as well as other modes. The coolant level is fine.

Thinking it was low on refridgerant, I took it to Jiffy Lube, they did an evacuation and recharge. Afterwards, the same problem. When I took it back the next day they tried to re-do it but they told me nothing was coming out during the evacuation as if all the refridgerant had leaked out overnight. I doubt this since if that were the case, the a/c wouldn't blow cold at all, even if just for 15 minutes. Plus I would think the compressor wouldn't spin if nothing was in the system but it doesn't. Must be something else.

Reading different posts, I see where the blend doors have been a problem on my model but I would think that if they were getting stuck i'd get a constant temperature instead of varying ones.

Where I live it's been over 90 degrees for the last week or so. Unbearable without working A/C.

Anyone have any thoughts, ideas or suggestions?

When the re-circ door breaks, it can leave the outside and inside intake vents open. The effect is that air travels in through the external port and into the passenger compartment like having a window rolled down all the time.

Seach HeaterTreater on this forum for diagnostic information and a fix.

Texster68

[Briandl]

Laredos don't have blend doors....

[-Joe-]

Originally Posted by Briandl

Laredos don't have blend doors....

why not? If he has manual controls they just wouldnt be auto controlled by a motor.


sounds like mabye a vacuum leak somewhere loosing vacuum to the doors.. Provided the system is charged and working correctly.

more info here/... http://www.wjjeeps.com/hvac_sub_assembly.htm

[Briandl]

Originally Posted by -Joe-

why not? If he has manual controls they just wouldnt be auto controlled by a motor.


sounds like mabye a vacuum leak somewhere loosing vacuum to the doors.. Provided the system is charged and working correctly.

more info here/... http://www.wjjeeps.com/hvac_sub_assembly.htm

I guess so...

[HighLonesome]

Had that happen and my system was overcharged. Builds more pressure when things get hot and trips the highside switch.

[Jeeples]

Originally Posted by five.nein

Had that happen and my system was overcharged. Builds more pressure when things get hot and trips the highside switch.

That would be a valid diagnosis, except that his compressor stays running the entire time.


My girlfriend had the same issue with her '03 WJ (4.7, no dual climate control), took it to a reputable shop where they checked out the A/C and narrowed it down to an electrical problem. They said based of their experiences (in particular with Chrysler vehicles) that the head unit (their term, not mine) that houses the HVAC controls may have a bad A/C switch (push button A/C in our case).

The tech took me for a test ride to show me his diagnosis. As soon as the A/C started blowing non-conditioned air, he gave the top of the dash a good solid whack and sure enough, cold air started to come out immediately. After doing this several times, I felt their were pretty spot on with their diagnosis.

At this point I have yet to tear into the dash and either replace the unit or make certain that there are no bad connections. FWIW, the HVAC control stack runs about $102 from the dealer.

[HighLonesome]

Originally Posted by Jeeples

That would be a valid diagnosis, except that his compressor stays running the entire time.

Good call.