'99 XLT Front A/C Blow Warm on Hot Day

1999 Ford Expedition 5.4 Litre

Symptoms: On cool day or park under shed on hot day - All A/C (front & rear) are OK. But on hot day and park under the Sun (when cabin temp. gets real hot) - Rear A/C blows very cold but front A/C blows warm for a while and would get very cold (work properly) after the cabin temp. get cooler, about 10 minutes.

Diagnosis: Have read lots of threads about the "Blend Door" & "Actuator" broken and stuck and ready to open the front panel. However, if the blend door and/or actuator are the problems, would the front A/C blow the same air temp. and not changing due to the cabin temp.

Would anybody experienced the same be kind to shed the light on this with explanation and solution (send to the dealer is not an option). I plan to spend the whole day this weekend (like previous thread said - most time will be spent to remove the front panel cluster to get to these units).

Greatly appreciate any help!

when was the last time your AC was recharged?

It's never been charged but my mechanic checked it last year when the symptoms began and he said it was OK. May be it's time to recheck it by myself. Thanks mc0311grunt

Simple checks,
1) with a cold engine, when you start up and a/c is on max you should get cold air out of the front vents until the engine warms up
2) Same as above - accumulator should be cold to the touch
3) This isn't as simple as the above - remove console and you will see the actuator for the blend door. Move from cold to hot and you should see the armature move the door.

Biggest pain is the rear screw that holds the diverter for the floor vents if you have to change the actuator. Totally out of sight & next to the firewall.

Thanks stamp11127.

Regardless of the engine temp., Front & rare A/Cs will blow cold when the cabin temp. is @ ambient (<100 degree F - like when I parked under a tree or in my garage or car port). However, the only problem is when I parked under the sun and the cabin temp. got real hot (may be around 150-200 degree F) only the front A/C will blow ambient when I start the engine and will get cooler (not cold) for the next 7 minutes or so until the cabin get cooler and it will blow cold (about 12 minutes after I cold started the engine). No problem with the rare A/C it will blow cold from start, regardless of the cabin temp.

Another observation, during the first 12 minutes while the A/C trying to cool down the cabin temp., the front A/C will blow warmer when stop at stop light and will get cooler when the car moved (or @ higher RPM). Once the cabin temp. gets cooler (<100 degree F), it will blow cold, even at stop lights.

It's been doing this consistently for the past 10 - 12 months (since last summer).

Need to know the low and high side pressures, check to make sure front a/c is on max and recirculate door is working correctly.