S185 Won't Start

[MWD]

Hello I have a 2004 S185 Turbo that won't start. When the key is turned to the start position there is nothing, the hour meter doesn't light up or beep, the only thing that comes up in the hour meter are the letters I n p u and what looks like the letter e but missing part of the letter. I have cleaned up the two grounds one on the cab at the other beside it on the body. I have cleaned up the battery posts and cables pos and neg I have cleaned up the connections on the starter I have cleaned up the pos cables for the large fuse above the battery I have checked the fuse panel for blown fuses checks ok I have moved relays around I have 12.5 volts at the right dash panel with the red wire I have removed the wires from the right plug in, cleaned them and closed them to tighten them up on the pins I have run a second ground wire from the battery to the cab and body grounds with no success. The battery shows 12.5 volts Until this week if the machine sat for a few weeks it would start but if you shut it off it won't start. The past few summers it would act up when it got hot and humid out. It would run if the right dash was removed and let it hang with a bungee cord around it. I figured it was the panel or the plug. I tried my panel in another machine and S150 and it worked. I don't know what to do now my electrical knowledge is limited. Any help is greatly appreciated. Peter