Help! A/C erratic on real hot days

[C-A-R-S]

Last week when temps here soared above 90, my A/C behaved strangely.
It started out cold and then blew warm for awhile then cold again as the car cooled off it started working correctly.
On the cooler mornings it works fine.
Scanned the system, no codes.
Will be cooler this week so I'll bet it works fine!
Any ideas?

 

[xlrlist01]

Last week when temps here soared above 90, my A/C behaved strangely.
It started out cold and then blew warm for awhile then cold again as the car cooled off it started working correctly.
On the cooler mornings it works fine.
Scanned the system, no codes.
Will be cooler this week so I'll bet it works fine!
Any ideas?

lack of gas?

 

[C-A-R-S]

lack of gas?

No, my guess is one of the sensors goes wacky when it sits in the sun.
A/c works great anytime the car hasn't been sitting in the sun!!!

 

[ccclarke]

You can check the driver and passenger vent sensors with a Tech 2 to ensure they are in close agreement with one another.

In addition, there is a cabin ambient air temp sensor near the ignition switch, (it has a little fan) an external temp sensor behind the front fascia, and a sun load sensor on the dash to monitor when it gets warmer.

If the sensors are working correctly and the rolling film door that directs air appropriately works, the problem may be in the CJ2 HVAC control unit.

CC

 

[C-A-R-S]

You can check the driver and passenger vent sensors with a Tech 2 to ensure they are in close agreement with one another.

In addition, there is a cabin ambient air temp sensor near the ignition switch, (it has a little fan) an external temp sensor behind the front fascia, and a sun load sensor on the dash to monitor when it gets warmer.

If the sensors are working correctly and the rolling film door that directs air appropriately works, the problem may be in the CJ2 HVAC control unit.

CC

When I tested the sensors they were all close, but it was not real hot.
I may have to wait until it gets rea hot again and retest.
Not likely to reach 90's here for a few weeks.

Thanks for the input.
I will post back when I solve this.


Am open to any ideas

 

[C-A-R-S]

Hasn't been in the 90's since I reported problem.
Blew out dash and under with compressed air, so far no recurrence.
This week end it will hit 90 so we will see!