This is an especially common problem with this truck. It is the forward/ reverse contactor. It give no codes. Replace the contactor, don't rebuild it. The contactor was warrantied for a year by Crown, but the tips only 90 days. The contactors can get weak coils and there was a little cushion washer that would bind up.. Crown blamed GE, and GE blamed Crown. If it an Albright contactor, replace it with the Albright for an RC3020-30. Crown will try to sell you a kit to replace the Albright with GE, but this was just a failed attempt to solve the problem. The GE contactor worked no better than the Albright. If it is GE, you must replace with GE. I replaced these all the time when working for Crown. This will work if everthing stays lit on the dashboard.

If the dashboard is going blank, you either have a battery problem or a commnication problem between the dashboard and the steering module. If a little green light is flashing a code 258 on the bottom of the dashboard, you have a communication problem. This is 2 flashes, 5 flashes, 8 flashes on the light. You also need to know that the transistor panel will not cause the display to go blank. I think you can unplug the panel, and the display will still work. It may show a code, but it will stay lit. The battery indicator may be blank, but your display will still work and show the hours, trouble codes, etc.

The communication problem is wiring or a bad steering or display module. If you are going to swap parts, swap your display or steering module with the other truck. I used to carry a spare display and a spare steering module from a scrap truck for the swap tronics style troubleshooting. Look at your plugs for your comm wires at the display, distribution panel and steering module. I think they are labeled comm+ and comm- on the wiring diagram.

Crownie has some good advice on the K-1 and the keyswitch. I would be looking at these. He also suggested checking the battery under a load. I would say anything under 17 or 18 volts when operating the truck is bad, and this is with a fully discharged battery. When charged ( and full of water), about 21 volts is about as low as voltage should go. This would be under full accceleration or full speed lift.