Yesterday and today I started my 07 2500HD/ diesel and the heater blower did not turn on. I'm sure it always worked in the past. I tried it with the key and the heater fan ran. I sat in the truck and tried the autostart again and it sounded like the fan started then stopped. Any ideas? At the same time after I lent the truck to my neighbour to tow their horse trailer out of the field the service trailer brakes came on. When it stops snowing/ raining I will check the fuses. Thanks and Merry Christmas.