I hardly understand that your pin 17 does not become 0v when you ground it to the chassis...
Are you sure that the wire you use to link pin17 and the ground is not cut ? Did you check the continuity of the wire with the multimeter between the 2 opposite points ?
I have a last suggestion for you.
Try to link pin17 to pin 10 or pin11 or pin12 of the blue connector (they are grounds of the tv module)