9/3/05: Maintenance Tip: Cab Air Conditioning

[Capt._Chaos]

We all know it's been a long, hot summer out there!

Hopefully most everyone was able to make it through the heat with very little (if any) air conditioning problems on their trucks.

With fall just around the corner, many who are just now experiencing A/C trouble may be thinking about putting off the repairs on it until some time next spring- NOT A GOOD IDEA! You WILL NEED IT TO WORK this winter!

What many people are unaware of is that most air conditioning systems are activated whenever you turn on your defrosters, even in the winter time! If your truck has a separate button for engaging the A/C, try using it with your defroster next time your windows fog up on the inside and see what happens- can you see clearly now?

Air conditioners are useful for dehumidifying air in the cab (evidence by the amount of water that drains out of the evaporator housing and onto the ground when they're in use). While driving in the winter and the heat is running full blast, it can get humid in the cab and cause the windows to fog up. Running the A/C when the defroster is in use will clear the windows a lot faster.

As a last resort, if the A/C is inoperative or not effective enough, lower each window down a few inches to allow some fresh air into the cab.

Keep the windows clear, and BE SAFE!

[Uncle Truck]

One thing I have noted is that the A/C compressor being used for defrost during the winter months is not necessary. Two ways to deactivate it. There is usually a single wire connector at the A/C compressor itself. Remove it and tape up both ends of the connector so the contacts don't get dirty. Second, there is often a fuse in the panel specifically for the A/C clutch- just remove it.

In doing so there will be a lot more heat available for the windshield defroster, and no undue use or stress to the A/C system during the winter.
:)

-UT-

[Uturn2001]

In doing so there will be a lot more heat available for the windshield defroster, and no undue use or stress to the A/C system during the winter.

Actually by not running the AC from time to time puts a lot more stress on the entire system. There are lubricants in the system that must be circulated in order to keep various O rings and other seals from drying out which can lead to refridgerant loss and premature component failure.

[Uncle Truck]

You are correct Uturn. I do put the fuse for the clutch back in every 2-3 weeks to cycle the system a bit during the winter. But as for the truck, a 2001 Columbia, the defroster does work better without the A/C system cycling during the winter. The windshield is so tall that unless the heat coming out of the defrost vents is as warm as can be, the upper 6" of the windshield will not clear with the cycling from the A/C. This is very important for me as I live in the snow belt of the northeast :chase:

-UT-

[Capt._Chaos]

When the defroster is in use, it works on the principle of using the A/C system to dehumidify the air to clear the windshield.

If you're having better results on your own by disconnecting the power to the A/C clutch, then to each their own.

I've also had good luck with cracking the windows down an inch on either side.

[HSLD]

I think Freightliner FLD Driver's Manual recommends running your A/C 5 minutes per month even during cool weather.

HSLD