Just want to know for sure; have you done this yourself and verified it? The problem is the drawings in the green book (the source for Bentley) contradict each other even on the same page. My page on speedometer notes points that out and that's why he contacted me -- to verify the possible wiring changes.

But swapping gauge and ground is exactly what I suggested he try last night. He was headed out on a long drive this morning, so I don't know whether it worked, but I just advised he be careful to ensure the + terminal did not get moved; only the gauge and ground. I offered my theory Volvo might have changed the wiring for just that reason -- to keep the swap from working, but not be destructive.

Hope to hear from you that you've personally verified what Bentley repeats:


--
Art Benstein near Baltimore

Apologies to the OP for the hijack attempt.