Quote Originally Posted by Dirty Jim View Post
Hello all, looking for some guidance.
I have:

1989 C1500
700r4 trans
5.3 stock DBC
Manual transmission standalone harness
Reworked chassis harness (speedometer, lights, ac etc)

PCM specs
Hardware Type: P01_P59
Calibration ID: 12202821 Hardware ID: 9386530

Truck starts runs and drives, and the speedo works as it should. The problem I am having is that it gets close to stalling when coming to a stop. I've read that i should be feeding the PCM a VSS signal. I "teed off" aka wired in parallel the VSS to both the truck harness and the VSS wires from the harness. After that, the speedo did not work nor did it really seem to fix the stalliong problem.

Any ideas?
Reverse the connection at the PCM for the VSS.

Honestly though I would delete the VSSB or DRAC behind the cluster and feed the speedo with the PCM output. Makes correcting the speedometer for gearing or tire size changes in the future much easier.