sirius wont stay plugged into headunit

After you get it plugged in, push up on the little locking tab and kinda tug on the wire at the same time. It should lock into place.

Took a little fiddling for me too, but I got it to lock.

 

On mine it took quiet a bit of force to get the plug to seat fully and lock in. Is the end of connector flush with the connector next to it?

 

try more tape. if not electrical, then scotch so you can regulate the thickness a bit better.
mine wouldn't stay in, but after a night of trial and error, I finally got the right thickness of tape and haven't had a problem...knock on wood...

 

The plug needs to be seated very firmly to get it to "click" into place and lock. Difficult to do as it's hard to get leverage in that hard to reach space.

Try a long flat bladded screw driver to give the necessary leverage. Reach through the left side glove box opening and place the flat of the screw driver blade on top of the white plastic plug. Now reach in through the vent opening and pull the screw driver shaft towards you ...hard.. to seat the plug. Mine gave a satisfying "click" when locked!

Tip: I was able to work the white wire harness block into the glove box opening and then out the front of that opening. This took a little maneuvering (not force) to get it to fit coming out.....but makes it much easier to work in behing the radio unit!