Check to see if you blew any fuses or burnt up relays or wires.
The engine speed sensor is responsible for relay info to tach via PCM. No engine speed sensor no tach.
If the engine speed sensor also energizes the ASD relay which informs the PCM its got 12 volts running thru it. It also tells alternator to charge some how.
Check engine speed sensor, connections,wires.
Of course if you have auto trans/cruise control and its working fine then it is not the engine speed sensor.
No ASD relay no charge.
Don't know why temp would be messed up unless the sensors lost ground or wires were burnt up in wiring harness. The PCM gives a ground for sensors. I believe they ground up on head by injector pump
If you can't find problem you will have to have garage charge batteries up. You won't need much juice to run the engine but you mite need power to run other things.
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Bill Thomas
Missouri Mule - 96 Wht 4X4 ST CC,5 spd, 3. 54, 8 ft bed, 1 ft high cheater boards.
99 Freightliner bl/wht FL60 ISB-5. 9 24v,215 hp,520 tq,6 spd, 3. 59 nsr,16 ft box, 19. 5 tires,Wt/gvw 11,000/23000