2003 EB Automatic HVAC not blowing out of dash vents

[DZTEDDIE]

2003 EB Automatic HVAC not blowing out of dash vents.
When I start up and turn on the AC to 60 degrees and fan on high in auto mode sometimes the dash vents blow strong.

Then I here the blower working at full speed but the flow is not gale force more like a gentle breeze. Sometimes it works full strength for quite a while other times it just blows a gentel breeze from the get go.

I think it maybe the air mixing vent actuator but not sure.

this is the part number 1L2Z19E616AA that I found but when I look it up it says will not fit a 2003 but some sites says it does.

I'm a looking at the fix or am I missing something and should be checking somthing else.

I do not want to just throw parts at the problem If there are other things I need to check first please let me know.

Thanks

 

[DZTEDDIE]

So I did a test yesterday. Outside temp was 113 on the display.
Turned the dash AC set to auto and the rear AC vent on with the temp at 60.
The rear was blowing at full force using rear controls for over 30 minutes out of the rear but the dash vents were just a gentle breeze.
Then the rear temp got warmer, so I turned the rear off and waited about 2 minutes and turned it back on. Blowing cold like before.
The dash vent was the same cold but gentle breeze.
Any ideas?
Thanks