Hi I had same problem as you, but i was racing and the car just cut out. The fan and steering worked but no throttle. I didnt wont to turn the speedo on again as it could burst in flames or somthing

. Also there were no lights and i couldnt enter the Mode or Setup devices, so i contacted SMD and sent it to them and they sent me a Warrenty repair Lrp sphere tc speedo.
My speedo did smell Burnt, does yours, if so its dead mate