Some random thoughts, can you just heat one module at a time, and see if the other one shows dead right after start? Or if you can borrow a module from someone, try yours without heat, and when/if it doesn't start, change to the good borrowed module and see what happens. I imaging you have the 4 pin modules. Another thing to maybe try if you have the ability to start on just one mag (separate mag switches) heat one module, and try to start on the other one, and if it doesn't start on the cold module, try right away on the heated one and see if it starts. Actually thinking about it some more, even if you have the ignition switch with mags 1,2, both, start, you could jury rig a wire to the starter solenoid and still try to start on just one mag by putting the switch on that mag. As far as ground wires go, I had one coil not producing spark, and looked at the grounds, and they all looked fine. I pulled the bad coil off, and the ground was still connected but I missed it. When I pulled the coil toward me, the plastic insulation on the ground terminal broke, and the coil came free. The wire had broken before, and the plastic was all that was holding it in place. When I checked the coil ground wire before I took it off, I pulled on it and thought it was ok, but if I had pulled a bit harder, the plastic would have broke then. I put a new terminal on and was back in buisness. JImChuk