1999 dodge ram v10 2500 i have no bus and no start along with no gauges. As for now i have pulled all found connectors and cleaned and replaced with dioelectri grease overhead shows cdd in display i have fire on ether i also have and buzzing until i pull o2 sensor fuse and if i pull fuel pump relay ,and relay, and o2 fuse gauges come back after a short crank please help odometer codes present are 920 921 999

 

try disconnecting all the major sensors and see if the no-bus will go away. then add them back one at a time and see if one of them will trigger it.

...start with the o2 sensors. the truck should run w/o them, although it'll trigger a cel which you can ignore.

here's an old thread from d o d g e t a l k remove the spaces from the link
http://www.d o d g e t a l k.com/forums/showthread.php?t=63590

 

Have unplugged all sensors that's how i found the o2 but still have no bus running at a loss here

 

i don't know either. but if the cluster is plugged in, and the pcm is triggering the 900 series CEL, then something about the cluster, or its wiring might be the problem.

check the white electrical plug with the center bolt in the PDC box beside the battery. i think? it might be the cluster wiring. mine needs replugging occasionally to clear the no bus, but i've never had the 900 CEL.

if bad comes to worse, you can get a new cluster from the junk yard for cheap. just match diesel/gas, auto/manual, gauges vs lights, tach/no tach, and the mileage of your choice. but w/o knowing for sure, it would be just a shot in the dark, as in throwing parts at it.

determining exactly what's wrong could require an expensive scanner, or a hour of dealer tech/scanner time.

you don't have any mouse or squirrel damage to the wiring harness do you.
unplug/replug pcm plugs too.

 

I reflashed pcmcia last night no luck this morning hit key fired rihht up no issues at all

 

The 900 series codes are cluster codes. They display on the odometer, the PCM doesn't have a clue. Basically, they are telling you the cluster is not communicating with the PCM....