Heater Settings for Winter Driving by an Alaskan Truck Driver
Ice Fog
When you encounter ice fog, a very hot windshield will be required. The best way to accomplish a hot windshield is with the temperature on high, set to defrost, fan on medium, and the sun visors down.
Most drivers assume the fan should be on high, but that’s not the case. This is due to the A/C. When the heater is set to defrost, the air going through the heater core actually goes through the air conditioning unit first. The air passes through the air conditioner to help dry it for better interior defrosting.
If you turn the fan on high you will be moving more cold air out of the A/C than the heater core can heat. A lower fan setting will put out much higher heat, albeit less volume. By lowering the sun visors you can help keep that heat against the windshield and out of your face.
Cold Snow or Blowing Snow
The trick here is a very cold windshield. By keeping the windows cold, the snow will not stick. Turn the heater and fan on very low down on the floor just enough to keep you from freezing to death.
Rolling up a sweatshirt or towel and placing it over the defroster vents on the dash will help keep heat from getting to the window. Some trucks have openings from the engine compartment in front of the windshield and this trick doesn’t work so well on them because heat comes up out of the engine and hits the windshield.
This also will not work if you have moisture in the cab such as snow on your boots, a damp jacket or wet gloves. The moisture will fog the inside of the windows and you will have to turn the defrost on. Depending on the humidity, this will not work in warmer snow as warm snow will even stick to a cold windshield.
Warm Snow or Freezing Rain
When encountering warm wet snow your windshield and wipers will probably be a mess no matter what you do. Hot defrost like you use for freezing fog is about the only option and then just roll your window down a bit to keep from melting. Once the wipers are coated to the point that they are worthless, your best bet is to pull over and knock the snow/ice off them. This is also a good time to wipe off the snow covering your tail lights too.
At times an aerosol can of windshield de-icer will help a lot. You can reach out around the open driver’s window and give the blade and windshield a soak. This works great when stopped for a stoplight. Be sure you know the aerodynamics of your truck if you try this trick when moving. De-icer blowing back in the window is not good for the eyes. Or so I hear.
Turn the defrost off when you are parked
As mentioned above, the defroster turns on the air conditioning, and when you’re parked, the air conditioning will cycle the engine fan. You’ve probably heard the truck sitting there idled up with the fan screaming every five minutes and wondered why. Even though the engine is not hot enough to cycle the fan, the air conditioning condenser is.
Blog by Kevin Lowery a 28 year veteran truck driver and Alaskan driver for 23 of those years.
For more articles on truck driving please click here or visit our partner Trucker Dump podcast!
