2019 ford flex Liftgate problems
 

I have a power Liftgate and one morning it just stop working I’ve tried to replace parts on it I’ve replaced the Liftgate module, motor, latch and switches I am lost for words here please help me
https://cimg5.ibsrv.net/gimg/www.for...9d2d9b4555.png

When you replace the module you more than likely need to program it otherwise it might not work 100% like switch is working but FOB isn't. If I were you I'd put the old module back and do a reset. A battery ground disconnect is probably not going to do any good, you need a capable ford specific scanner to reset the module. Foxwell NT510 Elite with Ford with bidirectional support should be able to reset that module and most other modules, and even program a new module. For software approach try forscan free trial and get the adapter on Amazon.
When you say STOP WORKING it's not specific enough. Does it move down but not up, or not all the way, or no power at all, and have you tried to lift it up by hand (just to simulate the struts movement) to help the motor while it is running? If it works that way, try to go buy new struts. If the struts are bad the motor has to work harder or not working at all when it's over its lifting limit.
BTW the "new member area" is for new member to introduce yourself, what ford you own where you live what you do for living. When you have a specific issue already, just post directly to the appropriate forum like this, Ford Flex.

Only way to open
 

The only way to open is to go into the back and manually open it by the emergency open when I use the clicker the lights come on but the truck doesn’t open or close and pushing the buttons on it doesn’t do anything either but when I use the clicker I hear a noise under the hood in the fuse box I’ve checked all fuses and relays and tried resetting by the battery also

When there is no power at all I'd disconnect the electrical connector at the liftgate, let say it has 4-pin, find out which terminal is the power feed and ground, and feed 12v directly to the liftgate for diagnostic purpose. Just like how you troubleshoot a window regulator motor and bench test it without the motor removal, you disconnect the connector, say 2-pin, one takes 12v the other is ground for UP, you flip them for DOWN, you run jumper wires directly from your battery.
If the liftgate works that way you might have a wiring issue instead of a bad module.

Even though it says invalid data from rear gate module and the code is coming from the ipc not the bcm

When you bench test the liftgate and it works, then you check that 4-pin connector and see where the 4 wires are terminated on the other end then you can check for resistance. Let say pin1 is the power feed, find a helper to push the button, you can also use a voltmeter to check on pin1.
Don't panic on the DTC, once the module is reset it might not show up anymore. If your scanner has freeze frame data you can see when that U0531 was set, last week or yesterday based on the odometer reading.
Too bad my alldata software supports any car up to 2007, don't have diagram on your Flex.

Could you tell me where I might be able to find a wiring diagram?

if our member etinpa is around he should provide you the diagrams.

So in summary what I would do:
1) put the old module back
2) bench test the liftgate
3) check the 4-pin connector, test each wires
If the bench test and wiring are good, then:
4) reset the module with my foxwell NT510 Elite and check for relevant DTC
5) run active test to open/close the liftgate with foxwell
if the liftgate is still not responding, my last resort is to:
6) install the new module
7) program it with my foxwell
8) run active test again and check for relevant DTC

If you live in the bay area you can borrow my foxwell.