A lot of great information RLMguy. Thanks for posting for us fellow sufferers. How do you know that little skin tag on the soon to fail drive controller is a thermistor? mine has 3 gray wires, the battery thermostat has 2 wires and is easy to test. Were you able to detect any damage inside your controller when you opened it up or just too much goo? My 2nd one just went bad so I might dig in to it soon if I don't just toss it in the heap.
I've been noodling how I'm going to do individual 12v charging but I can't find any information on how the lockout operates. Mine is stuck in lockout status due to me shorting my charge port. If I do individual charging I could just remove the charge port, I think, if I could figure out how to disable the lockout switch. I'm assuming it must receive a signal from the charge port via the blue wire and acts like a relay to interrupt the power but beyond that I don't know how it works.
Hi Mowitor. Thanks for the kind words - just trying to help out others anyway I can with my sagas.
Great point on the thermistor. Just went out and confirmed (cut off the coating on my failed controller), that what I thought was a thermistor is an unused connector (on the drive controller) not shown in the service manual (my bad) - I'll edit my previous post. This is a bummer, as I was hoping there was some sort of correlation of heat related shutdown - as many seem to post that the mower "resting" for some time gets it to move again (odd if not somehow heat related). I also was confused on one person saying they had an "H" on their gauge. Would like to understand that response better.
On opening the controller box, "goo" is probably not the best description. Its goo that the entire electronics board was dipped in and then the goo hardened (almost plastic like). This I believe is to conduct the heat to the casing. As a result - I don't see how you can service anything. Its completely encased in goo.
On the interlock, I tried to understand the wiring, but as you say - its confusing. It appears plugging IN the charger shorts two port pins which in turn cuts off main power availability. Its tied in with the seat switch also. If your port "short" remains, that would explain the lockout. The service manual has a connector to connector wiring diagram but not really a schematic diagram - which is what is needed. Its got to be a simple bypass somehow however. I think the port assembly is relatively cheap compared to a controller. Are you saying your mower is completely down (locked out due to your port issue)?