We were ready to leave Bay City, Michigan on Thursday morning when I tried to start the engine, nothing. The dash lit off, the batteries showed 12.6 on my VMSpc. It was like there was a lockout on the start. We looked at the transmission, it was OK as far as starting as was everything else. I called Tiffin and talked to Danny who said he thought there was a fusable link near the starter solenoid. I could not find one. I called Spartan who said he did not think there was a fusable link but suspected a relay. He had me check several fuses and relays in the aft drivers side fuse box, nothing. No power to the starter solenoid. He recommended being towed to Cummins Bridgeway in Saginaw, MI. I finally started the engine using the old fashioned way, a screwdriver (actually two screw drivers) across the contacts. I was able to drive the 20 miles to Cummins Bridgeway without being towed. On my way there I got three "stop engine" warnings and my VMSpc showed the engine AND transmission temps in the 230 range. When I slowed the stop engine went off. Cummins Bridgeway got me in a bay in 10 minutes!!! When I turned the ignition switch off the engine continued to run. The tech finally stopped the engine by pulling a 60 amp fuse from the starting batteries. The tech worked for two hours trying to diagnose a bad relay or bad ignition switch etc. At 3:00 they had a shift change. The new tech continued to work on the relays with numerous calls to Spartan and wiring diagrams faxed back. Not finding anything after about four hours he had me take the engine cover off and he unplugged the ECM. When he did, three pins came off in the plug, they were completely corroded off and a fourth was also green with corrosion. We had found the problem!!! We because I was working the ignition switch at their commands etc. The Saginaw dealer did not have the ECM for the Cummins ISL in stock but their Hudson MI store did. They immediately sent their driver on the three hour round trip. By 11:00 pm they had the ECM in hand. While waiting, the tech removed the exhaust system so that he could remove the ECM and removed the ECM. He began replacing the ECM and reprogramming it. Then he replaced the exhaust system. AT 12:50 AM THEY HAD THE ECM REPLACED AND HAD THE MOTORHOME RUNNING!! We spent the rest of the night in their yard with hookups. I have never heard of or seen a company that would work to 1:00am to get you up and running. Many, many kudos to Cummins Bridgeway in Saginaw Michigan. Excellent, also stayed until 1:00 AM.