Conversations with CampyTime (Wendy) encouraged me to check my rear window weep holes. It's obvious that the weep holes in this window have never worked. They are effectively sealed by a plastic track in the bottom of the window frame.
I lifted the end of the plastic track a couple of inches with a flat bladed screw driver and clipped about an 1/8th of in inch wide piece off the weep side edge of the track for the distance of about an inch. I used a pair of wire cutters to do this. Pushing the track down I can now see light
through the bottom of the track through the weep hole. Water flows easily. I did this on both ends.
After wetting this area for the flow test, I wiped it with a paper towel removing most of the accumulated dirt.
Thanks for the push Wendy.