Quote Originally Posted by 1BadAction View Post
The DRAC on a 91 suburban is around the area that the column bolts to the dash. You need to run a VSS wire from it to the 7427 to get a speed readout to the PCM. No idea why, but this was how I had to do mine to have the MPH readout in the datastream and get the 80E to shift correctly.
Cool, thanks. I'll take a look next time I have the dash apart. Is it a white, translucent box like it is on the later trucks? I just don't remember seeing it last time I was in there. But it's kind of a moot point now since I'm running a parallel VSSB from a '94 that provides the speed signals to the PCM. Seems to be working OK.