Lift gate open and stop have way

This sounds like a signal/switch issue. Check the tail lift switch. It may be a button built into either the tailgate or the frame it sits in. It'll will probably be a spring loaded button that is pushed in when the lift gate is closed.
Also check the wire harness that feeds from the body to the lift gate. These flex every time you open and close the lift gate so the wires inside can wear out or snap over time.

In link below of owners manual starting page 223 fuse box diagram I see two fuses for lift gate, one for module and the other is for logic.
https://cdn.dealereprocess.net/cdn/servicemanuals/chevrolet/2016-equinox.pdf
The link below problem found was switch in side vehicle was turned to off position.
https://chevroletforum.com/forum/tahoe-suburban-25/power-liftgate-stopped-working-36262/

https://www.youtube.com/watch?v=caThwc07PyU

https://www.youtube.com/watch?v=SdQuQyG78SI

https://www.youtube.com/watch?v=KbSAcgAzIZM
On video below it talk about adjustment of latch. If not opening right move latch around and attempt to open liftgate..
You might try closing latch with door open and push button to see latch open up. If it opens fine it could be binding when door is actually closed and latch needs adjusting.
https://www.youtube.com/watch?v=AmPIx4GuEkc

https://www.youtube.com/watch?v=nno-epcZxQc
https://www.youtube.com/watch?v=pBievVsXBLE

I have a 17 Terrain which does not have power lift gate. Something I notice in the video was if you have power lift gates it says to step back when opening and closing because there are sensors to prevent someone from being hit with the door.

Here is how it works !
Liftgate Locking Operation
The lift gate will lock any time the vehicle is shifted out of park on vehicles equipped with an automatic transmission and at vehicle speeds exceeding 5 kph with manual transmission. This happens in conjunction with auto door locks if enabled or independently of auto door locks if the feature is disabled. This ensures that the lift gate is locked anytime the vehicle is shifted out of park or when the vehicle is in motion.
The lift gate lock relay supply and coil sides receive a constant voltage through the battery voltage supply circuit and the ECC fuse. The normally closed contact is connected to ground and the control side is connected to the body control module (BCM). A lock function will occur when a door lock switch activation, keyless entry lock transmission, auto door lock function or a lift gate lock function has been received by the BCM. The BCM will then ground the control side of the lift gate lock relay. This energizes the relay and allows voltage to be applied to the lift gate lock actuator lock control circuit. Since the other side of the lift gate lock actuator is connected to the normally closed contacts of the door unlock relay to ground, the lift gate will lock. When an unlock function occurs the BCM will ground the control side of the unlock relay and the rear doors and lift gate will unlock.
The BCM also runs diagnostics on the lift gate lock relay control circuit and will set DTC B3825 as current and also send a Class 2 message to the DIC. The DIC will display REPLACE LIFTGATE FUSE to inform the driver that a fault has been detected in the lift gate lock circuit and that the lift gate is not locked. Faults that will set the DTC and cause the DIC to display the message could be any of the following:
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An open ECC fuse

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An open or short to ground in the lift gate lock relay battery positive voltage circuit

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A faulty lift gate lock relay

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An open or short to ground in the lift gate lock relay control circuit

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A short to ground in the lift gate lock actuator lock control circuit

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A faulty BCM

Check it out on you tube !

try open the left back door first then the outher one

Insert the key and turn the lock cylinder while lifting up on the lift gate. You have to get the gate open. Once open, The strike plate (where the locking mechanism hits) is bolted to the jamb. Loosen the bolts and slightly move it toward the rear of the vehicle. NOT TOO MUCH!
Tighten the bolts, and try it. Hope this helps.

did lift gate get repaired ? warranty ? what was replaced? $ cost to customer?

try removing your shocks/struts for the lift gate. once removed, check to see if they fully extend in and out of the barrel. You may have bent shocks/struts. Also, check to see there is nothing preventing the lift-gate from opening such as a bolt or acorns between the spoiler and the roof...

The support shocks on the rear door need to be replaced. You can find them at your local auto parts store. They are VERY easy to install. Compare prices before you buy. Prices vary.

There is a switch in the lift gate latch that closes when the gate is closed and turns off the light, this switch is defective, replace it and the light will go off.