Does anyone know where to connect the speed sensor on an 2000 H1 Hummer . It seems to be to one of the connections on the Digital Ratio Adapter. These are the connections documented in the Service Manual. One person I spoke to said one of the unused pins might have a signal that would work.

Pin 1 not used

Pin 2 not used

pin 3 not used

Pin 4 Cruise Control Reference Signal 4000PPM

Pin 5 Blank

Pin 6 Blank

Pin 7 Vehicle speed Sensor RETURN

Pin 8 Ground

Pin 9 12 Volt ignition Signal

Pin 10 Seedo Reference Signal

Pin 11 Not used

Pin 12 Vehicle speed

Pin 13 Output Shaft Revolution Signal

Pin 14 Not Used

Pin 15 Not used.

I was wondering if I need to connect to one of the wires or if one of the unused pins would have a signal that I could connect to.

From what you posted, I'd try tapping into pin 10 or pin 4.

If those don't work, you can tap a yellow wire behind the speedo, not too hard to get to. Tach is also yellow, so make sure you test, test, test.....

I connected the VSS wire to pin 15 or the DRAC. The pins are not well documented in the HUMMER service manual, but with some help of the Hummer network, I was told that there are several outputs that could be used. So far, this seems to be working well and the 3d mode is also working. I think one could also hook in to pin 14 as well.