Speedometer issue

[apd855]

I put a 03 5.3 P59 into an 02 Trailblazer which originally had the 4.2. I managed to get the gauge cluster to read everything correctly. My only issue is with the speedometer. The speedo will not register until I get to about 27 mph. At that speed the needle will jump up and read correctly beyond that. Not really an big deal, just a little irritating, and would like to get it working properly.


Piece of additional info. To get my speedo to read correctly, I had to adjust the ABS pulses to 4000.

[apd855]

Resolved my problem. I have a unique situation where I'm trying to retain the operation of all the factory systems in the trailblazer. What I found is that I had the wires on pins 49 & 50 of the green plug swapped going to the vehicle. Pin 49 is the speed output signal for the ABS and 50 is for the speedometer. Probably won't apply to anyone, but thought it might help someone in the future.