Help Diagnose Liftgate Issue

[jjrdha]

I was hoping I could get some help diagnosing a problem with my liftgate.

All of a sudden, the tailgate only opens about halfway and stops, regardless if I use the remote, handle or button inside the car. The tailgate will open all the way if I push it up manually.

For closing, the tailgate does close all the way, but it appears the car doesn't think it is closed. The little interior light on the tailgate stays lit and I get a message on the console say the tailgate is ajar.

After searching on google, I did check the height adjustment setting and checked to see if there was any water in the liftgate control unit. None there.

I'm thinking there is 1 of 2 issues:
- Liftgate control module is bad and needs to be replaced
- One or both of the lift arms is bad and needs to be replaced

Question is, does anyone know how to determine if it is one or the other besides taking it to the dealer and paying the diag fee?

thank you.