98.5 3500. Very cold here, about -30. Don’t have a block heater yet. Cycled my grid heater 3 times, tried to start it and starter cranks for about 10 seconds before it dies down slower and slower. Usually will jump but wouldn’t jump today. Brand new batteries, all good connections. Never an issue until it gets cold. Please any help appreciated. Trying to get my truck into the garage so I can install my block heater and new blower motor.