Dear fellas,
I have a 1994 GMC K2500 Suburban. Original engine was 454 big block but died and replaced with Isuzu diesel. I maintained 4L80e and used an independent transmission controller from TCI.
The independent controller requires the VSS signal so I connected its terminal to the VSS sensor in the transfer case. Furthermore, the controller also has a speedo signal cable with a 12V square signal. Signal PPM (pulse per mile) is programmable with the controller and I maintained it at 4000ppm which is the same as the VSS buffer from the vehicle. I connected controller to light blue / black cable that goes to the speedo and worked. While testing it got undone, I reattached it with engine running (I know, I know....it´s a no no) and now speedo does not work. I tried everything. I pulled the instrument cluster out and it does not seem to have any burned integrated circuits and all resistors and capacitors seem OK. Even weirder, when I ground the speedo wire (light blue -black) to the vehicle, in a pulsating manner by hand, I get the speedo and the odometer to move and show speed.
What is going on? Please help!
I have a 1994 GMC K2500 Suburban. Original engine was 454 big block but died and replaced with Isuzu diesel. I maintained 4L80e and used an independent transmission controller from TCI.
The independent controller requires the VSS signal so I connected its terminal to the VSS sensor in the transfer case. Furthermore, the controller also has a speedo signal cable with a 12V square signal. Signal PPM (pulse per mile) is programmable with the controller and I maintained it at 4000ppm which is the same as the VSS buffer from the vehicle. I connected controller to light blue / black cable that goes to the speedo and worked. While testing it got undone, I reattached it with engine running (I know, I know....it´s a no no) and now speedo does not work. I tried everything. I pulled the instrument cluster out and it does not seem to have any burned integrated circuits and all resistors and capacitors seem OK. Even weirder, when I ground the speedo wire (light blue -black) to the vehicle, in a pulsating manner by hand, I get the speedo and the odometer to move and show speed.
What is going on? Please help!
