It's still very difficult to test for breaks in the grid since no matter which line one is testing there are always other parallel circuits which could give a false reading.
Aside from a brand new grid or installing a window and testing it on a moist cool day, I don't know of a way that I could test the grid at the pick and pull before taking the rear glass out.

Phil Forrest

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1972 220D "Trudy," named by a friend.

"The 220D sounds good... I suspect it is the only car that you need a calendar for, rather than a stopwatch, when doing acceleration tests."
Tom Abrahamsson