I am a diesel tech at oil field trucking company and have a 2007 pete 386 cummins isx pre-emissions The tach speedo quit working along with the trip miles and hour meter. It shows miles when the key is off but gives lines when key is turned on. Trouble shooting so far, 1. Swapped relays behind gauges and checked fuses and replaced even though showed good. 1a. Checked wires behind fuse panel to insure power. 2. Checked power and grounds to gauges and icu. 3. Swapped icu box with same year make and model truck known to work. 4. Swapped gauge cluster with same year make and model truck known to work. 5. Checked voltage to gauge cluster from donor truck and compared with problem truck ( matched to within half a volt.). 6. Checked and cleaned engine ecm and cab icu connectors. 7. Ohm'ed wires from icu to gauge cluster( checked good) 8. There are no codes when plugged in cummins insite. Me and the other mechanic are out of ideas on what else it could be. Any help would be greatly appreciated.
Tried disconnecting the batteries, let sit for a few then hooking them back up?? My 2013 and 2018 pete’s when they’ve replaced the numbers with dashes thats whats fixed the issue. Remember the gauges are run by the CECU not the engine ECM.
Left over night with batts disconected and 2007s have an ICU instead of a Cecu. Looks exactly the same though just says icu instead.
and the drive said they quit when he turned on the jakes but thats not to say that they were out when he did that and thats just when he noticed.
