2006 Eaton Fuller push button console wont come on.

Hope someone can help me.
I have a 2006 Volvo VNL 670 with D12, Eaton Fuller shifter attached to the seat. I cant find any info on what speed the tranny is. There is only a throttle and brake pedal. I recently bought the truck with a bad ECM. Truck would crank but not start. Ordered a reman ECM and the truck would run. Go into gear with no issues. Then, the trans controller would not turn off when I shut the truck off. Disconnected the batteries, replaced the two fuse holders, fuses and associated wiring. Replaced the ignition switch, still the controller would stay on. I disconnected the batteries again and now, the controller wont come on. Fuses in the battery box are good. Batteries are new. Went back to my original ignition switch and still wont come on when I turn the key on. Ive checked all the fuses and relays in the center of the dash. One other thing, when I turn the key off from the ignition being on, after about 10 seconds of turning the key off, the service light in the controller will flash once. Im also not getting any communication with the TCM when I try to retrieve the codes. This thing has me stumped! Any help would be greatly appreciated! Thanks!

 

Sorry for the delay. .

 

Lazer?

 

Thanks Wore Out! Hopefully someone will chime in about the trans controller problem.

 

Thanks bjytech! Ill download the manuals and see where it takes me. Ive got a good Fluke multimeter. Hopefully its something obvious and not the TCM. Thanks again!

 

I done some research previously that bad grounds could cause problems like this. Has anyone else run across this?