Have a 98 3.9l that when first started the cluster comes on the fuel guage works the tach comes up but give it gas and tach dont move. Then after a few seconds the tach drops and fuel guage and other guages stop working the odometer starts flashing and warning lights stay on the truck still runs and drives great. Have changed cluster with a different one and does same thing. Any ideas on where to go next would be appreciated.

 

On the 98, the cluster gets its clue what to do with the various lights/gauges from the PCM. If it doesn't get that signal, it panics. Not sure which wires are for comms on your truck.....

 

Cluster is on BUS I believe. So it's likely losing Buss communications somewhere. Could be where the harness enters the cluster, or anywhere downrange from the previous factory splice (I believe the CTM but could be wrong).