My Truck wouldn't heat up so I change the thermostats (using Startlet) the old ones had rubber missing. So I flushed the whole system put everything back together and the truck still won't heat up. I unplugged the fan and put cardboard in front of the rad, went for a drive and still no heat.
Started my truck this morning and noticed my interior lights are flashing. I shut the truck off, opened the door and the lights stay on.
What doses it mean?